When we set about to study the nature of abrogation in the Qur'an, there is an important fact that we must first consider. By abrogation is not meant the abrogation of the verses per se, rather, it has only been the legal decrees in these verses that were abrogated. The verses in the Qur'an which contain the abrogated laws serve to show how it was that the divine revelation influenced the evolutionary history of a community as a whole. The Qur'an has never been a book of morality alone; it is also a book of guidance for societal change.
In having retained verses, the rulings enshrined in which were themselves abrogated, it was, perhaps, the purpose of God to show the reformers of every age how it was that a society which was culturally and civilizationally a non-entity, was positively transformed on the firm foundations of divine guidance; this was in addition to showing how the Qur'anic directives were to be implemented under such circumstances.
As far as the community of Muslims is, concerned, such verses are of educative value and so they are of of prime relevance. The basic sources of Islam are the Qur'an and the practices of the Prophet. It is the duty of the scholars in every age to find the solutions to the problems that present themselves continually before the society at large; solutions that are formulated in the light of these most basic of sources. When confronted with every new problem, the scholars must provide for solutions that are based on an acute understanding of the stands taken by the Qur'an and the Prophet whenever the resolution of a similar problem comes up before them. This would not be possible in the absence of a sound knowledge in the positions adopted by the Qur'an and the Prophet in varying, circumstances.
In the cases of abrogation, although the law has been replaced, if the verses which were revealed in varying circumstances had not been preserved the Muslim community could have faced the bleak prospect of groping in the dark when faced with such situations. Here, too, it becomes clear to us that these verses have served only to prove the truth of the Qur'an being revealed by the Creator Who has the knowledge ebout everything.