وَمَغَانِمَ كَثِيرَةً يَأْخُذُونَهَا ۗ وَكَانَ ٱللَّهُ عَزِيزًا حَكِيمًا
The verse is a second object attached to the verb athābahum (He recompensed them) in verse 18: He gave them a near fatḥ and many spoils that they will take.
And the choice of word is meaningful. In the fifteenth verse maghānim was the thing those left behind asked for; here the same word is what is given to those who pledged. The same word stands in two different places four verses apart: in one it is asked for, in the other it is given.
The verb is in the imperfect: yaʾkhudhūnahā — "that they will take", "that they are taking". Something that has not yet happened is recounted as though it were happening.
This pair of names comes for the second time in the sūra (7 and 19). And in both places the context is the carrying out of a decision: in the seventh verse a punishment, here the realisation of a division of spoils.
And its place here is particularly meaningful. To whom spoils are to be given is a question of division, and divisions give rise to dispute — indeed it is exactly this dispute that the sūra recounts (15). The verse closes the division with two names: ʿAzīz (whose decision cannot be turned back) and Ḥakīm (whose decision is in its proper place).