Expositor's Bible Commentary Commentary Romans 4:20

"yet, looking unto the promise of God, he wavered not through unbelief, but waxed strong through faith, giving glory to God," — Romans 4:20 (ASV)

The final value of Abraham in respect to justification is that his faith becomes the standard for all believers. “Against all hope,” this man believed. In view of his “deadened” condition (and that of Sarah likewise) because of advanced age, the situation seemed past hope. Nevertheless, he believed the promise of God that offspring would be given. “In hope” (GK 1828) takes account of the great change that came over his outlook because of the pledge God gave him. After making the original promise (Genesis 15:5), God waited until it was physically impossible for this couple to have children. Then he repeated his pledge (Genesis 17:5). Abraham’s act of faith was essentially the same as on the previous occasion, but meanwhile circumstances had made the fulfillment of the promise impossible apart from supernatural intervention. He was shut up to God and was able to rest his faith in God alone.

He “faced the fact” of his physical condition and that of Sarah and “did not waver through unbelief.” The refusal to waver answers to the refusal to weaken in faith. Abraham apparently suffered a momentary hesitancy (Genesis 17:17), but it passed and was not held against him. That he really trusted God for the fulfillment of the promise is seen in his readiness to proceed with circumcision for himself and his household before Isaac was conceived (Genesis 17:23–27). This act in itself could be construed as giving “glory to God,” an expression of trust in the power of the Almighty to make good his promise. Moreover, it was an open testimony to others of his trust in God’s faithfulness to his word.

As far as Abraham was concerned, he was not taking a chance. He was “fully persuaded” that God’s power would match his promise. This man of God was called on to believe in a special divine intervention—not after it occurred, as the Jews were challenged to do concerning the resurrection of Jesus (Acts 2–5), but before. His faith is the more commendable because it was exercised in the face of apparent lack of necessity. Would not Ishmael do as the desired progeny? He had been born to Abraham through Hagar in the interval between the original promise (Genesis 15) and its renewal (Genesis 17). Abraham was willing to rest in the wisdom as well as in the will of God. Verse 22 probably refers to the original statement of Abraham’s justification, emphasizing that his ability to meet the renewed promise of God by unwavering faith was strictly in line with the faith that brought justification at an earlier point (v.3).