Paul concluded his proof that faith was the only method of justification before the Cross by showing that what Abraham did in trusting God is essentially what everyone must do.
4:18 Abraham's hope rested solely on God's promise. He had no hope of obtaining descendants naturally. His faith was not a condition for the reception of the promise, but he believed with the intention of receiving it.138
4:19-21 Even though Abraham's faith was stronger at some times than it was at others (cf. Gen. 17:17, 23-27), Paul could say he was not weak in faith (v. 19).
"When Paul says that Abraham did not doubt . . . because of unbelief,' he means not that Abraham never had momentary hesitations, but that he avoided a deep-seated and permanent attitude of distrust and inconsistency in relationship to God and his promises [cf. James. 1:6-8]."139
The patriarch believed God in the face of discouraging facts that he contemplated courageously. He believed despite the knowledge that what God had promised could not happen naturally. Abraham grew stronger in faith as time passed. The record of his life in Genesis shows this (v. 20). He gave glory to God by believing Him.
4:22 This verse brings Paul's argument concerning Abraham's justification to a climax. The apostle had proved the point he set out to demonstrate, and he restated Genesis 15:6 as a conclusion (cf. v. 4).
"The spiritual attitude of a man, who is conscious that in himself he has no strength, and no hope of a future, and who nevertheless casts himself upon, and lives by, the word of God which assures him of a future, is the necessarily and eternally right attitude of all souls to God. He whose attitude it is, is at bottom right with God."140
