Surah 37. As-Saffat, Ayah 143

I.e., to remember God and to repent: see 21:87 , which reveals in its very formulation the universal purport of Jonah's story.

 Before being swallowed and while inside the whale (see 21:87). The lesson is: good deeds are of great help during difficult times.

"But he cried through the depths of darkness, 'There is no god but Thee: glory to Thee! I was indeed wrong!' " (xxi. 87).