The second son's refusal and the Gentiles' condemnation
Theophilus is explaining the parable of the two sons in Matthew 21:28–32, and has just described the first son, the Gentiles, who repented and went into the vineyard.
When the first son—the Gentiles—had refused, the Father went to the second son—that is, to Israel—who, being called through Moses, said, “All that God has spoken, we will do and we will hear.” But they neither did nor heard, nor did they repent afterward. The prostitutes and the tax collectors—that is, the Gentiles—condemned them.