Tafsir of Al-Anbiya' 21:72

"And We granted him Isaac and Jacob as a nafilah (gift)." That is, a bestowal, as has been narrated from Mujahid and ‘Ata’, derived from nafaltuhu, meaning "I gave to him."

According to what Abu Hayyan chose, it is like al-‘aqibah (the consequence) and al-‘afiyah (well-being), and it is in the accusative case (mansub) as an object of wahabna (We granted), in the same manner as the phrase qa‘adtu julusan (I sat, a sitting). A group of scholars opted for the view that it is a circumstantial qualifier (hal) pertaining to Isaac and Jacob, or [referring to] a child of a child. Or [it may mean] an addition to what he, peace be upon him, had asked for, which is Isaac; thus, it would be a circumstantial qualifier pertaining to Jacob, and there is no ambiguity in this due to the evident contextual indication.

"And all of them"—referring to those mentioned: Abraham, Lot, Isaac, and Jacob, peace be upon them, all of them without exception—"We made righteous."

That is, We granted them success to attain righteousness in [both] religion and the world, so they became perfect.