Ye People of the Book! Why dispute ye about Abraham, when the Law and the Gospel Were not revealed Till after him? Have ye no understanding?
Ah! Ye are those who fell to disputing (Even) in matters of which ye had some knowledge! but why dispute ye in matters of which ye have no knowledge? It is Allah Who knows, and ye who know not!
Abraham was not a Jew nor yet a Christian; but he was true in Faith, and bowed his will to Allah’s (Which is Islam), and he joined not gods with Allah.
Without doubt, among men, the nearest of kin to Abraham, are those who follow him, as are also this Prophet and those who believe: And Allah is the Protector of those who have faith.
The argumentation referred to in verse 65 was to decide whether
Sayyidna Ibrahim (pbuh) followed the way of the Jews, or that of the
Christians. The futility of their exercise already stood exposed as both
these ways in religion appeared long after the revelation of the Old
and New Testaments. These just did not exist before that. How, then,
could it be claimed that Sayyidna IbrahTm ,WI+ adhered to these
Verse 66 points out to the hollowness of their approach when they
indulged in their argumentation on the basis of incomplete knowledge.
That they would venture to do so on the basis of no knowledge could
hardly he explained. The truth is that only Allah knows the way of Ibrahim (pbuh)
That way has been described in Verse 67.
Verse 68 declares that the closest of people to Sayyidna Ibrahim
were those who followed him during his time and now the closest to
him is the Prophet of Islam, Muhammad al-Mustafa (pbuh) and
so are the believers in him and in past prophets. These believers are
the community of Muhammad (S) and their guardian is Allah
and He will reward them for their belief.
Shafi, Muhammad (2008). Maariful Quran. (Vol .2 surah 3 pg. 94). English-MaarifulQuran-MuftiShafiUsmaniRA-Vol-2.pdf (islamicweblibrary.com)