This is given as a reason why God must act as he is said to act in verses 9-10: there is no respect of persons, no partiality, no favouritism towards any man of any nation. Jew and Gentile are treated equally by God.
It doesn't matter to God if you're clever or if you're uneducated or simple. It doesn't matter to God if you're rich or if you're poor. If you're skilled or so-called unskilled. All that matters is that you give up being contentious and rebellious and sinful and unbelieving, and you say, ‘Lord, forgive me, save me, change me. I trust in Christ Jesus, the Saviour of the world and what he's done for me. I want to be changed and to have fellowship with God and a new life.’ That's what the passage is all about. It's the gospel. They say the letter to the Romans is a doctrinal book. Well, here is the gospel, almost before the apostles got started, and it's going to be a very practical epistle all the way through.
Isn’t election an act of favouritism? Doesn’t God show favour to one and not to another without any regard to human deeds? Yes, he certainly does, for he set his love upon his people even before they had done good or evil, and even before the world was created. But this is not favouritism in the sense meant here by the apostle, because God’s love towards his elect took no account of anything in them. It was rooted in his sovereign will, in his good pleasure alone, about which he gives no explanation to us. This is not favouritism, because the basis of it is not something in human beings, but something totally outside of them. When in another passage Peter also concludes that God is no respecter of persons (Acts 10:34), he says this because in making his choice the Lord ignores any distinction which men might take into account. Election therefore undermines and bypasses all favouritism, for God takes no account of anything in his chosen people when he predestines them. The one who shows favouritism towards another, has abandoned strict justice. He has his eye more on the benefit to that individual than to justice and truth. But though God set his love upon us from eternity, the way of salvation is rooted in justice; it is established by the law. Grace may deprive hell of one victim, but it substitutes another in his place. This is not favouritism. It is favour, it is love, but it is not favouritism. It is in perfect harmony with justice.
The call of the Gentiles underlines this principle. It is God’s even-handedness with regard to Jew and Gentile that demonstrates that favouritism is not to be found in God. God could never have been guilty of favouritism even in Old Testament times when salvation was largely limited to Israel, for then too it was by election and some were chosen and others passed over. But the Lord reinforces this lesson when he removes the possibility of such an accusation by calling the Gentiles. This removed also the possibility of misunderstanding in the mind of the Jew. This was the lesson that impressed itself so forcefully upon Peter, for the Jew also needed to learn that God deals with all in the same way: by grace.