God does not dramatically change His mind. Rather, He employs dramatic ways to keep us within His plan of salvation. We can attempt, like the lawyer, to trick God. He knew very well what he had to do to gain eternal life. Or we can, like Jonah try to run away from God, to run away from His mission.
The story of Jonah is full of paradoxes: all other prophets speak in poetry, while Jonah, in prose; all others preach to the Israelites, Jonah to foreigners; others fail to convert Israel but Jonah against his will succeeds in converting the pagans. The Assyrians are more open to God's grace than the Israelite prophet! It is the foreigners who teach the prophet to pray even if he prefers to sleep. They want to preserve him but he wants their destruction (Jonah 3:4 and 3:10-4:1).
It is the outsiders who are converted — the despised, the rejected, the heretics, the people whom we hate and look down upon or who have taken advantage of us. Jesus asks us today to listen to them, to listen to the Samaritans as they teach us to pray and follow God's will, as they care for their neighbour silently.
We who are so-correct and "anxious to justify" ourselves can in fact be so biased and self-righteous; so proud and pious that we miss the signals of wonder and goodness flashed to us through the "darkenss" around us.
Lord, give me the grace to overcome my prejudices and to recognize the signals of wonder and goodness.