ثُمَّ يُجْزَىٰهُ ٱلْجَزَآءَ ٱلْأَوْفَىٰ
Summa yujzaahul jazaaa 'al awfaa
and that in the end he will be repaid in full for it;
and then be repaid for it in full,
Awfa is the elative form of wafa, to pay in full, the language of weights and measures where a debt is discharged to the last portion. Wafa also opened this passage a few verses back, describing Ibrahim as the one who fulfilled what was asked of him; what a person renders there returns here as what is rendered to him. The construction doubles the verb with its own noun.