"May the God of hope fill you with all joy and peace in believing, so that you may abound in hope by the power of the Holy Spirit" (Romans 15:13).
We are working with the idea that faith is looking to the power of God to do in us what we cannot do ourselves. That is precisely the kind of faith that Abraham had. In a previous epistle Paul had said, "Just as Abraham believed God, and it was reckoned to him as righteousness, so, you see, those who believe are the descendants of Abraham" (Galatians 3:6). In this chapter it is faith in the power of God that enabled both Abraham and Sarah to do the totally impossible when they were way past childbearing age (Romans 4:19-22).
4:1-3 If Abraham had been put right by his own efforts in giving birth to Isaac, he would have had something to be proud of (3:27). But since all our perfecting is by the freely given power of the Spirit, none of us can claim the credit for what God does in us. "By grace you have been saved through faith, and this is not your own doing; it is the gift of God - not the result of works" (Ephesians 2:8,9).
4:4-5 Anything that is done by our own efforts is more like a wage, but faith in God's agency results in us being put right by totally unmerited grace.
4:6-8 The quotation from Psalm 32:1-2 reminds us that as we turn to God our past failure is not counted against us. But Paul knew that the Psalm goes on to say that, instead of his strength being dried up (Psalm 32:4), the Psalmist is forgiven, delivered, taught, surrounded with steadfast love, and having been made upright he can shout for joy (Psalm 32:5-11). That sounds remarkably like what Paul will offer as the blessing of faith in the Spirit's empowering in Romans 8.
4:9-12 Paul had explained the meaning of heart circumcision in 2:25-29. Now he further explains that in Abraham's case the heart faith preceded his circumcision. And it was this heart faith that characterizes all true believers regardless of whether or not they are circumcized (as in Galatians 3:6-9). It is interesting that in our world both Jews and Muslims still practice circumcision as a sign of their commitment to God.
4:13 In Galatians Paul pointed out that the faith experience of Abraham not only preceded the rite of circumcision but it preceded the giving of the Mosaic law by 430 years (Galatians 3:17).
4:14-15 If the heirs of Abraham had been those who tried to be put right by law, then the promise to Abraham of being a blessing to all nations would have been voided. All that the law can do is point out our inability to meet God's standards. So if there was no Mosaic law in Abraham's day then violations of the law were not even in view.
4:16 This means that both Jews who follow the Torah and others who have the same kind of faith as Abraham can share fully in the promise to Abraham by faith alone.
4:17-18 The faith that makes us faith children of Abraham is believing in the God who "gives life to the dead." In the case of Abraham that meant looking to God who could give the power for conception from the deadness of Sarah's womb.
4:19 In a previous epistle Paul connected the power that Abraham believed in with the power of the Spirit. "The child who was born according to the flesh persecuted the child who was born to the Spirit" (Gal. 4:29). A theological explanation would be that Ishmael was born by the predictable regularities of science. Isaac was conceived by faith in the intervention of the Spirit.
Similarly under Romans 1:16 we noted that Luke's Gospel gives an explanation in terms of the power of the Spirit in Mary's womb. "The Holy Spirit will come upon you and the power of the Most High will overshadow you." And it was Mary's "let it be with me according to your word" that resulted in her bringing forth the Messiah.(Luke 1:35, 38).
4:20 In Abraham's case the promise that he would father "a great nation" was given before he left Haran (Genesis 12:2). When Abraham complained he was still childless, God said "your very own issue shall be your heir" (Genesis 12:4). And when God said his descendants would be as numerous as the stars, Abraham believed God's promise. Then he thought of the common practice of having heirs through Hagar, but God still promised him an heir through Sarah who was by then way past childbearing age. Abraham believed what Mary was also told in the same situation, "Nothing will be impossible with God" (4:21; compare Luke 1:37).
Evidently our faith in God's power will not have the same context as Abraham's. Among the many examples of faith listed in Hebrews 11 we read that Abraham "received the power of procreation, even though he was too old - and Sarah herself was barren." In the sacrifice of Isaac "he considered the fact that God is able even to raise someone from the dead - and figuratively speaking he did receive him back." In every case faith is looking to God for empowering in that particular person's situation (Hebrews 11:23-38).
4:23-25 For us there is a similar faith in the power that raised Jesus from the dead. Having seen the power of the resurrection, we then know that we can also be put right by the power of the Holy Spirit from whatever present fear, failure, or frailty we are experiencing. And the doxology is "Now to him who by the power at work within us is able to accomplish abundantly far more that all we can ask or imagine, to him be glory in the church and in Christ Jesus to all generations, forever and ever" (Ephesians 3:20-21).