With respect to the Qur'an, there are two types of naskh that occurred. There is a general naskh, in which the Qur'an abrogated the previous scriptures that were revealed to other nations, and there is the specific naskh, in which some verses of the Qur'aan abrogated others.
Both of these types have benefits behind them:
From the beginning of time, Allaah has revealed to mankind a general code of belief and set of law that will guide them to a better life in the world, and provide for them an everlasting life in the Hereafter.
The most important of this message and one that has remained a constant theme for all the prophets, is that of the oneness of Allaah (Tawheed).
"And verily We have sent among every nation a messenger, (saying), worship Allaah alone, and avoid all false deities."(Q 16[NahI]:38)
Included with the belief of Tawheed was the belief in messenger (Risaalah) and belief in the Day of Judgment (Akhirah). The fundamental of belief (aqeedah), remain unchanged for all the prophets and Messenger in all time and place.
However, as a manifestation of Allaah's Mercy, mankind was not left without guidance in his social and political life. Rather, their Creator provided for them a set of law that will govern them in mutual affair, and instruct them concerning all that was beneficial for them, and warned against all that was harmful to them.
This code of law varied from time to time, and from place to place for each set of people has their specific problem and peculiar situation that needed to be catered to Allaah says:
"And from every nation We appointed (their) religious ceremony, so that they may mention the N a m e 0 f Allaah. " (Q22 [Hajj]:34)
Since each prophet was sent to a different nation, it was possible for one messenger to abrogate the law of a previous messenger.
"(And Eesa said to his people) I have come confirming that which was before me of the Tawrah, and to make lawful for you part of what has been forbidden to you." (Q3[Aal-Imraan]:50)
In other words, the law that Eesa (alayhi salaam) came with were meant to abrogate the law of Musa.
With the coming of the religion of Islaam, all previous laws and religion were abrogated. And whoever, seeks a religion other than Islaam, it will never be accepted from him." (Q3[Aal•lmraan] :85)
The role and status of the Qur'an with respect to other religion is made clear in the following verse:
"All We have sent down to you (O Muhammad) the Book in truth confirming the scripture that came before it and a muhaymin over it." (Q5 [Maidah]:48)
The word Muhaymin mean that the Qur'an is a witness over the previous scriptures, so that all that conforms with it from the previous scriptures is accepted, and all that contradicts it is rejected. The Qur'an, therefore, acts as a naasikh agent over the previous scriptures which are mansookh when they conflict with the Qur'an.
This is one of the greatest blessings of the Qur'an, for it shows that it is the most complete Book (since nothing can abrogate the Qur'an after), and that it is superior to all other scriptures (since it abrogates all previous books). It also demonstrates the superiority of the Ummah of the Muhammad (salallahu alayhi wa sallam) over all other nations, since the set laws that have been revealed to it is perfect for all and suitable for all nation, at all times. This is in contrast to all other laws which were only meant for a specific nation, at a specific time.
This article was culled from the publications of Deen Communication Limited