The Quran

وَإِذا غَشِيَهُم مَوجٌ كَالظُّلَلِ دَعَوُا اللَّهَ مُخلِصينَ لَهُ الدّينَ فَلَمّا نَجّاهُم إِلَى البَرِّ فَمِنهُم مُقتَصِدٌ ۚ وَما يَجحَدُ بِآياتِنا إِلّا كُلُّ خَتّارٍ كَفورٍ

Muhammad Asad

For [thus it is with most men:] when the waves engulf them like shadows [of death], they call unto God, sincere [at that moment] in their faith in Him alone: but as soon as He has brought them safe ashore, some of them stop half-way [between belief and unbelief].¹ Yet none could knowingly reject Our messages unless he be utterly perfidious, ingrate.

Cf. 17:67, as well as 29:65, which says - in a similar context - that "they [begin to) ascribe to imaginary powers a share in His divinity" (yushrikun). The parable of a storm at sea is, of course, a metonym applying to every kind of danger that may beset man in life.