Romans 4:21

And therefore it was imputed to him for righteousness. Not because his faith was strong, and he had a full assurance of it, but because it was right, resting on the promise of God, and relying upon…

And being fully persuaded - Thoroughly or entirely convinced; Luk 1:1; Rom 14:5; 2Ti 4:5, 2Ti 4:17. He was able - Compare Gen 18:14. This was not the only time in which Abraham evinced this…

And being fully persuaded - πληροφορηθεις, his measure: his soul was full of confidence, that the truth of God bound him to fulfill his promise and his power enabled him to do it.

Having observed when Abraham was justified by faith, and why, for the honour of Abraham and for example to us who call him father, the apostle here describes and commends the faith of Abraham, where…

he staggered not, &c. The Gr. suggests the paraphrase; "he looked away from his own physical state, only at the Promise, and did not doubt its terms just because they were the Promise. So he rose in a…