For God has concluded them all in unbelief, that he might have mercy upon all.
Read Chapter 11
Ambrosiaster
AD 400
From earliest times all nations lived in ungodliness and ignorance because they were without God. For this reason the law was revealed, by which the worst ones could be restrained. But by the activity of the adversary sins began to multiply, so that through the commandment man was considered more guilty still. Then God, who in the mercy of his goodness always takes care of human creation, seeing that even without the law sin still existed and that by the law it could not be wiped out, decreed that he would require only faith, by which the sins of all men might be abolished. Thus although man had no ground for hope through the law, he was nevertheless saved by the mercy of God. To consign everything to disobedience means that this decree comes as a gift from God at a time when everyone was laboring in unbelief, so that grace might appear to be the freest of all rewards. Therefore nobody should boast, for the one who is proud of his ignorance is to be pitied. Commentary on Paul’s Epistle...
The apostle did not mean by these words that God would not condemn anybody. What he meant is made clear by the context. Paul was speaking about those Jews who would one day believe.
T to the disobedience of men; and set forth why it is that one and the same God has made some things temporal and some eternal, some heavenly and others earthly; and understand for what reason God, though invisible, manifested Himself to the prophets not under one form, but differently to different individuals; and show why it was that more covenants than one were given to mankind; and teach what was the special character of each of these covenants; and search out for what reason "God.
And therefore Paul declares, "For God hath concluded all in unbelief, that He may have mercy upon all; "