The sign of Jonah

Holy Gospel of Jesus Christ according to Saint Luke 11:29-32.
While still more people gathered in the crowd, he said to them, "This generation is an evil generation; it seeks a sign, but no sign will be given it, except the sign of Jonah.
Just as Jonah became a sign to the Ninevites, so will the Son of Man be to this generation.
At the judgment the queen of the south will rise with the men of this generation and she will condemn them, because she came from the ends of the earth to hear the wisdom of Solomon, and there is something greater than Solomon here.
At the judgment the men of Nineveh will arise with this generation and condemn it, because at the preaching of Jonah they repented, and there is something greater than Jonah here.

Commentary of the day
Saint Irenaeus of Lyons (c.130-c.208), Bishop, theologian and martyr
Against the heresies III, 20, 1 (cf SC 34, p. 339)

The sign of Jonah

God showed patience in the face of man's weakness because he saw beforehand the victory he would eventually give him through his Word. For, when «power was made perfect in weakness» (2Cor 12,9), the Word caused God's goodness and tremendous power to be made manifest.

Indeed, it was the same with man as it was with the prophet Jonah. God permitted Jonah to be swallowed by a sea-monster, not to make him altogether vanish away and die but so that when he had been vomited out by the monster he would become more subject to God and would give all the more glory to him who had given him this unexpected deliverance. It was, too, to lead the Ninevites to firm repentance and to convert them to him who would deliver them from death, amazed as they were by the sign accomplished in Jonah... In the same way, God permitted man to be swallowed by that great monster, the author of disobedience, not so that he should altogether vanish away and die but because God had prepared beforehand the salvation fulfilled by his Word by means of the «sign of Jonas». This salvation has been prepared for those who have the same feelings for God as Jonah did and who confess him in the same words: «I am the servant of the Lord and I worship the Lord, the God of heaven, who made the sea and the dry land» (Jon 1,9).

God desired that man, by receiving an unanticipated salvation from him, would rise from the dead and worship God, saying with Jonah: «Out of my distress I called to the Lord; from the midst of the nether world he heard my voice» (Jon 2,2). God desired, too, that man would always remain faithful in giving him worship and unceasing thanks for the salvation he has received from him.

courtesy of the daily gospel