مَا نَنسَخْ مِنْ آيَةٍ أَوْ نُنسِهَا نَأْتِ بِخَيْرٍ مِنْهَا أَوْ مِثْلِهَا أَلَمْ تَعْلَمْ أَنَّ اللَّهَ عَلَى كُلِّ شَيْءٍ قَدِيرٌ  أَلَمْ تَعْلَمْ أَنَّ اللَّهَ لَهُ مُلْكُ السَّمَاوَاتِ وَالأَرْضِ وَمَا لَكُمْ مِنْ دُونِ اللَّهِ مِنْ وَلِيٍّ وَلاَ نَصِيرٍ البقرة: 106-107

"Whenever We abrogate a verse or leave it, We bring one better than it or one equal to it. Do you not know that Allah is powerful over everything? Do you not know that to Allah alone belongs the kingdom of the heavens and the earth? Other than Allah, you have neither a patron, nor a helper." [al-Baqarah: 106-107]

(مَا نَنسَخْ) "Whenever we abrogate a verse" - abrogation linguistically is removal and transcription. It is said, "The wind removed (nasakhat) the remnant", and "I transcribed (nasakhtu) the book", that is I copied what was in it. Its shar'i meaning is the lifting of a ruling derived from an antecedent (prior) text and its replacement by a ruling derived from a subssequent text.

"or cause it to be forgotten" has two meanings; it is ambivalent (mutashabih). It can be from forgetting (nisyan), that is, Allah made his Messenger (saw) to forget so it was forgetten and lifting, or it can be from leaving without substitution, that is, we do not abrogate it, as in the His (swt) saying, (نَسُوا اللَّهَ فَنَسِيَهُمْ)"They forgot Allah so He forget them" [at-Tauba: 67], meaning they left Allah so He left them.

This word(نُنسِهَا) nunsiha, has another mutawatir recitation - nansa'ha - as recited by the two imams Abu ‘Amr and Ibn Kathir, from amongst the seven recitations, whilst in the remaining five it is recited as (نُنسِهَا) nunsiha, with a dhamma on the nun. And the word nansa'ha is as in your saying, "I delayed (nasa'tu) this matter".

Thus the meaning is ‘or we delay it', such that we do not we abrogate it, rather we leave it without abrogation. This recitation is defintive (muhkam), since it only holds one meaning, and as it is known in Usul, the clear (muhkam) takes precedence over the ambiguos (mutashabih). Therefore, the meaning of forgetting is overridden and the meaning remains one, irrespective of whether it is read nunsiha or nansa'ha, namely, we delay it and do not abrogate it. This is because the two recitations are both mutawaatir, and the meaning of both is one, that is,

مَا نَنسَخْ مِنْ آيَةٍ أَوْ نُنسِهَا "whenever we abrogate a verse or delay it", means whenever we abrogate a verse or leave it without abrogation.

(نَأْتِ بِخَيْرٍ مِنْهَا أَوْ مِثْلِهَا) "We bring one better than it or one equal to it", that is, upon abrogation, Allah the Exalted brings a verse that is better than the abrogated verse, or one equal to it. Thus the response clause, (نَأْتِ بِخَيْرٍ مِنْهَا) "We bring one better than it" is for the conditional verb(نَنسَخْ) "we abrogate", that is, "whenever we abrogate a verse, we bring one better than it or one equal to it".

As for the mention of "or we lift it", it means we lift it without abrogation, as long as the response clause does not include it. Thus what I deem the correct meaning, with the help of Allah, is that it is for the additional knowledge that Allah (swt) abrogates verses leaves others without abrogation. Had "whenever we abrogate a verse we bring one better than it or one equal to it" been mentioned without the mention of "or we lift it", there would have been a possibility of understanding from the verse that all the verses are subject to abrogation, whereas with the mention of "or we lift it", that is, we leave it without abrogation, that possibility is removed and it is affirmed for us that there are verses in which abrogation occurs and there are other verses in which it does not.

The saying of Allah, the Exalted, (أَوْ مِثْلِهَا)"or one equal to it" is literal, that is, we bring verses equal to the abrogated verses. As for "one better than it", the literal meaning here is impossible because no one verse is better than another; all of them are the speech of Allah. Here we must move to the metaphorical meaning with the assumption of an omitted word "ruling" before "verse", that is, we bring a verse the derived ruling wherefrom is better than that ruling derived from the abrogated verse. Thus, abrogation of a verse occurs with a verse equal to it, or with a verse wherein the ruling is better than the ruling in the abrogated verse.

This is analogous to the omission in the verse (وَاسْأَلْ الْقَرْيَةَ) "and ask the city..." [Yusuf: 82], that is, ask the people of the city, due to the impossibility of asking the city in reality. Likewise in the verse (وَأُشْرِبُوا فِي قُلُوبِهِمْ) "and their hearts absorbed..." [al-Baqarah: 93], that is, absorbing the love of the calf, due to the impossibility of absorbing the calf into their hearts, and thus is "we bring a verse better than it", that is, better than the ruling of it, because no one verse is better than another.

As for some rulings being better than others, this can occur in a number of ways:

1. It is an immediate betterness, such as a ruling being abrogated and a lighter ruling being set in its place, or no new ruling being placed, thus the immediate, perceptible betterness lies in the ease of its fulfilment.

2. It is a delayed betterness, of reward in the Hereafter, such as a ruling being abrogated and a ruling being set in its place whose execution is more difficult thus the betterness lies in the increase of reward received on the Day of Resurrection, given the increased difficulty that lay in the fulfilment of the new ruling with respect to the fulfilment of the abrogated ruling. Here the benefit is delayed until the Hereafter.
Thus the noble verse carries the following meaning:

Allah the Exalted lifts certain verses without abrogation, and He abrogates other verses and when He abrogates a verse, He brings another verse which is equal to it, or one which is, with respect to the ruling therein, better than the abrogated verse - the betterness in the ruling is as we explained, either immediate given the ease of its fulfilment in this dunya, or delayed with an increase in reward in the Hereafter.
As for the saying of Allah (swt):

((أَلَمْ تَعْلَمْ أَنَّ اللَّهَ عَلَى كُلِّ شَيْءٍ قَدِيرٌ * أَلَمْ تَعْلَمْ أَنَّ اللَّهَ لَهُ مُلْكُ السَّمَاوَاتِ وَالأَرْضِ وَمَا لَكُمْ مِنْ دُونِ اللَّهِ مِنْ وَلِيٍّ وَلاَ نَصِيرٍ))

"Do you not know that Allah is over all things competent? Do you not know that to Allah belongs the dominion of the heavens and the earth and (that) you have not besides Allah any protector or any helper?" [al-Baqara: 106-7] This is a rhetorical question for affirmation, that is, the hamza here is for affirmation and it is an address to the Messenger of Allah (saw), "Certainly, you know that Allah is over all things competent, and he controls all matters and directs them, and He knows that which reforms his slaves, thus he abrogates some rulings and establishes others and there is no one who can reject his command, and there is no protector nor any helper for any of his slaves, other than Allah, the Exalted.

The question here is for the purposes of affirmation, analogous to the saying of the Exalted,
(أَلَمْ نَشْرَحْ لَكَ صَدْرَكَ) "Did we not expand for you your breast?" [Ash-Sharh: 1] that is to say, indeed, We expanded for you your breast. Likewise His saying (أَلَيْسَ اللَّهُ بِكَافٍ عَبْدَهُ) "Is not Allah sufficient for His servant?" [Az-Zumar: 36], that is, Allah is sufficient for His servant.
A note about abrogation
Abrogation, as we have said, is the lifting of a legal ruling (hukm shar'i) acquired from an antecedent text and the placement of a different legal ruling in its place, acquired from a subsequent text. For there to abrogation, the following matters are required:

1. A clear, subsequent text in place of an antecedent text in the same subject matter of the ruling.

2. An indication in both texts which clearly indicates the abrogation of the ruling of the antecedent text; it does not suffice that there be the mere appearance of contradiction for abrogation to occur.

3. The abrogation occurs in the rulings and not in the fact/information [khabr], since information from Allah, the Exalted, does not carry anything but definitive truth; hence there is absolutely no abrogation of it. All of what has been related of abrogation - through the examination of the texts - is regarding the legal rulings, exclusively.

4. There is no abrogation of recitation, for there did not occur abrogation in the recitation of any verse, hence for all of what was revealed of the Qur'an - that which lay between the two covers of the mushaf - there is no recitation of any single verse that was abrogated. As for what has been narrated through solitary reports of what is claimed to be Qur'an, then that is not Qur'an, because the Qur'an is the miracle of the Messenger of Allah (saw) and the definite proof against mankind, meaning that it came to mankind with certainty - through concurrent (mutawatir) transmission - because it used to be revealed upon the Messenger of Allah (saw) then he (saw) would to recite it unto the people in groups, and it was written from the writers of revelation, and with the like of this, solitary transmission does not occur, because it was not recited upon individuals, rather upon groups, and because Allah, the Exalted, protects it,
(إِنَّا نَحْنُ نَزَّلْنَا الذِّكْرَ وَإِنَّا لَهُ لَحَافِظُونَ) "Indeed, it is We who sent down the Qur'an and indeed, We will be its guardian" [al-Hijr: 9]. This means that it reached us through certainty, without any scope of error. All of this proves that what is transmitted through solitary reports is not Qur'an. T there is no Qur'an other than what is between the two covers, wherefrom all of it is recited, and there is no recitation therein of any verse that was abrogated and this is a definite proof of the non-occurrence of abrogation in recitation rather it is in ruling, exclusively.

5. Verses are not abrogated except by other verses. This is because Allah (swt) says,
(وَإِذَا بَدَّلْنَا آيَةً مَكَانَ آيَةٍ) "Whenever we replace a verse with another verse" [al-Nahl: 101], that is, indeed Allah (swt) abrogates a verse with another verse. Likewise, what came in the previous verse, "whenever we abrogate a verse or leave it, we bring one better than it or one equal to it", since Allah the Exalted is the one who brings that which abrogates a verse, that is, the abrogating evidence is a verse, since this is what Allah (swt) brings, because the Qur'an is the speech of Allah (swt). As for the Sunnah, albeit revealed from Allah (swt) to his Messenger (saw), however it is revelation by meaning. As for its wording, then it is ascribed to the Messenger of Allah (saw), and hence it does not abrogate the Qur'an, regardless of whether it is mutawatir or speculative (dhaniyy), since the two previous verses both indicate that a verse is not abrogated except by another verse.
As for the Sunnah, it can be abrogated by the Qur'an and the solitary (ahad) hadith can be abrogated by both the mutwatir hadith and the solitary hadith, in the way explicated in the relevant chapter of the science of usul al-fiqh.

6. Abrogation differs from ‘specification of the general' (takhsees lil ‘aam), for abrogation lifts an antecedent ruling in its entirety, whereafter it is not acted upon, whereas specification lifts a portion of the general ruling, not from its entire basis. Hence praying whilst facing Masjid al-Aqsa (the first qiblah) was abrogated, and the Ka'bah was set as the qiblah in its place and thus was prayer made towards the new qiblah - the Ka'bah - meaning the first ruling - of prayer towards Masjid al-Aqsa - was abrogated conclusively, hence this is abrogation.

As for specification of Zakat on grazing cattle as established by the hadith «في الإبل السائمة زكاة» "There is Zakat on the grazing camels" (Baihaqi, Hakim), that which specifies the hadith of zakat on general cattle - those which are grazing and others - is the hadith

«فإذا بلغت الإبل إحدى وعشرين ومائة ففي كلّ أربعين بنت لبون وفي كلّ خمسين حقة» "and when (the number) of camels reaches one hundred and twenty one, then on every forty camels, one bint labun (she-camel in its third year) is due, whilst on every fifty, one hiqqah (she-camel in its fourth year) is due" (Bukhari). Thus Zakat was not lifted from the camels in general, rather it was lifted from other than the grazing and working camels, that is a the ruling was lifted from a part of the general, hence this is specification of the general and not abrogation of it.

7. Through the examination of the texts about abrogation it becomes clear that the type of the new ruling with respect to the abrogated ruling, falls under three states:

a. The new ruling is lighter than the abrogated ruling
Whether it be through the lightening of its fulfilment (الآنَ خَفَّفَ اللَّهُ عَنكُمْ وَعَلِمَ أَنَّ فِيكُمْ ضَعْفًا) "Now Allah has lightened your burden and He knew that there is weakness in you" [al-Anfal: 66], or the removal of a ruling entirely, without (the bringing of) a new ruling -
(أَأَشْفَقْتُمْ أَنْ تُقَدِّمُوا بَيْنَ يَدَيْ نَجْوَاكُمْ صَدَقَاتٍ) "Have you become afraid of offering charities before your consultation?" [al-Mujadalah: 13]

b. The new ruling is equal to the abrogated ruling
The first qiblah - Masjid al-Aqsa - was abrogated with a second qiblah - The Sacred Ka'bah - "Al-Bara' b. ‘Azib reported, I prayed with the Prophet (saw) facing Bait ul-Maqdis for sixteen months until this verse of Surah al-Baqarah was revealed: ﴿حَيْثُ مَا كُنتُمْ فَوَلُّوا وُجُوهَكُمْ شَطْرَهُ﴾ "And wherever you are turn your faces towards it". This verse was revealed when the Prophet (saw) had said his prayer. A person amongst his people passed by the people of Ansar as they were engaged in prayer. He narrated to them (this command of Allah) and they turned their faces towards the Ka'bah." (Muslim). The ayah,

((قَدْ نَرَى تَقَلُّبَ وَجْهِكَ فِي السَّمَاءِ فَلَنُوَلِّيَنَّكَ قِبْلَةً تَرْضَاهَا فَوَلِّ وَجْهَكَ شَطْرَ الْمَسْجِدِ الْحَرَامِ وَحَيْثُ مَا كُنتُمْ فَوَلُّوا وُجُوهَكُمْ شَطْرَهُ))

"We have been seeing you turning your face towards the heavens. So, We will certainly assign to you a Qiblah that you would like. Now, turn your face in the direction of the Sacred Mosque, and (O Muslims) wherever you are, turn your faces in its direction" [al-Baqarah: 144]. Hence this verse indicates the abrogation of the first Qiblah and it is equal to the ruling of the new qiblah, which is the Sacred Ka'bah.

c. The new ruling is more difficult than the abrogated ruling
The abrogation of the obligation of fasting the day of Ashura - Narrated ‘Aisha: The Quraysh used to fast on the day of Ashura' in the Pre-Islamic period, and then Allah's Prophet ordered to fast on it till the fasting in the month of Ramadhan was prescribed; whereupon the Prophet (saw) said, «من شاء فليصم ومن شاء فليفطر» "He who wants to fast (on ‘Ashura') may fast, and he who does not want to fast, may break fast" (agreed upon) with the fasting of Ramadhan,

يَا أَيُّهَا الَّذِينَ آمَنُوا كُتِبَ عَلَيْكُمْ الصِّيَامُ كَمَا كُتِبَ عَلَى الَّذِينَ مِنْ قَبْلِكُمْ لَعَلَّكُمْ تَتَّقُونَ - أَيَّامًا مَعْدُودَاتٍ فَمَنْ كَانَ مِنْكُمْ مَرِيضًا أَوْ عَلَى سَفَرٍ فَعِدَّةٌ مِنْ أَيَّامٍ أُخَرَ وَعَلَى الَّذِينَ يُطِيقُونَهُ فِدْيَةٌ طَعَامُ مِسْكِينٍ فَمَنْ تَطَوَّعَ خَيْرًا فَهُوَ خَيْرٌ لَهُ وَأَنْ تَصُومُوا خَيْرٌ لَكُمْ إِنْ كُنتُمْ تَعْلَمُونَ - شَهْرُ رَمَضَانَ الَّذِي أُنزِلَ فِيهِ الْقُرْآنُ هُدًى لِلنَّاسِ وَبَيِّنَاتٍ مِنْ الْهُدَى وَالْفُرْقَانِ فَمَنْ شَهِدَ مِنْكُمْ الشَّهْرَ فَلْيَصُمْهُ

"O you who believe, fasting is prescribed upon you as it was prescribed upon those before you that you may become God-fearing. For days few in number. However, should any one of you be sick or on a journey, then (he should fast) a number of other days (equal to the missed ones); and those who have the strength (but do not fast), on them there is a compensation (fidyah), that is the feeding of a poor person. Then whoever does good voluntarily, that is better for him. However, that you fast is better for you, if only you knew. The month of Ramadhan is the one on which the Qur'an was revealed, as guidance for mankind, and as clear signs that show the rights way and distinguish between right and wrong. So those of you who witness the month, must fast in it..." [al-Baqarah: 183-185]. Thus the fast of ‘Ashura' was abrogated with the fasting of Ramadhan, whilst the latter is more difficult.