Rom 4:1 Abraham was, humanly speaking, the founder of our Jewish nation. What did He discover about being made right with God? Rom 4:2 If his good deeds had made him acceptable to God, He would have had something to boast about. But that was not God's way. Rom 4:3 For the Scriptures tell us, "Abraham believed God, and God counted him as righteous because of his faith."
Once again Paul points out that works will not get you into God’s graces. Faith in him during the time of Abraham and after Christ entered the world, faith in the son was necessary.
Rom 4:4 When people work, their wages are not a gift, but something they have earned. Rom 4:5 But people are counted as righteous, not because of their work, but because of their faith in God who forgives sinners. Rom 4:6 David also spoke of this when he described the happiness of those who are declared righteous without working for it: Rom 4:7 "Oh, what joy for those whose disobedience is forgiven, whose sins are put out of sight. Rom 4:8 Yes, what joy for those whose record the LORD has cleared of sin."
You work all your life at a job or raising children and when you turn old you live on what you have earned. We can work for God all our lives and that would be good thing unless you never accepted the Son. You would collect nothing at the end. If a person accepts Christ on Monday and is hit by a bus on Tuesday, he or she collects everything. That does not seem fair does it. In our times there is virtually no one who has not heard of Christ. There may be a few but they have to be hidden in the recesses of the most remote place on earth. If you have heard the Word, then you know that repentance for you sins and acceptance of Christ is the only what to heaven. Joh_14:6 Jesus told him, "I am the way, the truth, and the life. No one can come to the Father except through Me.
Rom 4:9 Now, is this blessing only for the Jews, or is it also for uncircumcised Gentiles? Well, we have been saying that Abraham was counted as righteous by God because of his faith. Rom 4:10 But how did this happen? Was he counted as righteous only after he was circumcised, or was it before he was circumcised? Clearly, God accepted Abraham before he was circumcised! Rom 4:11 Circumcision was a sign that Abraham already had faith and that God had already accepted him and declared him to be righteous—even before he was circumcised. So Abraham is the spiritual father of those who have faith but have not been circumcised. They are counted as righteous because of their faith.
Circumcision practiced today but for sanitary reasons not spiritual. I am sure that the non-messianic Jews believe it is necessary but that would not be true.
Rom 4:12 And Abraham is also the spiritual father of those who have been circumcised, but only if they have the same kind of faith Abraham had before he was circumcised. Rom 4:13 Clearly, God's promise to give the whole earth to Abraham and his descendants was based not on his obedience to God's law, but on a right relationship with God that comes by faith.
The promise to give the whole earth to Abraham and his descendants is found in Gen_12:2-3 and Gen_15:5
Rom 4:14 If God's promise is only for those who obey the law, then faith is not necessary and the promise is pointless.
Rom 4:15 For the law always brings punishment on those who try to obey it. (The only way to avoid breaking the law is to have no law to break!)
Life Application New Testament Commentary 4:14-15 If people must obey God’s law and be good enough in order to be saved, then faith is useless. That, in turn, would make God’s promise also meaningless. If the law does not bring righteousness, then why does it exist? The law brings punishment. In other words, in a world where people can make real choices, the law’s presence automatically includes the possibility of failure and the consequences that would follow. The law’s function is to help people realize their great sinfulness and to impose penalties on those who transgress it. The only way to avoid breaking the law is to have no law to break. If no one defines right and wrong, then no one knows the difference, and no one can sin.