Tafsir of Al-Isra 17:66

{يُزْجِي}: It means to make flow and to move.

{وَالضُّرُّ}: It refers to the fear of drowning.

{ضَلَّ مَن تَدْعُونَ إِلَّا إِيَّاهُ}: Every being you call upon during your calamities vanishes from your concerns and thoughts, except for Him alone. At that moment, you do not remember anyone else, you do not call upon anyone else, you do not pin your hopes on anyone else’s mercy, and it does not even cross your mind that anyone other than Him is capable of rescuing you. Or, it means: those you call upon among the gods have failed to rescue you, but Allah alone is the One you hope in—an exception of disconnection (istithna' munqati').

{أَفَأَمِنتُمْ أَن يَخْسِفَ بِكُمْ جَانِبَ الْبَرِّ أَوْ يُرْسِلَ عَلَيْكُمْ حَاصِبًا ثُمَّ لَا تَجِدُوا لَكُمْ وَكِيلًا * أَمْ أَمِنتُمْ أَن يُعِيدَكُمْ فِيهِ تَارَةً أُخْرَىٰ فَيُرْسِلَ عَلَيْكُمْ قَاصِفًا مِّنَ الرِّيحِ فَيُغْرِقَكُم بِمَا كَفَرْتُمْ ثُمَّ لَا تَجِدُوا لَكُمْ عَلَيْنَا بِهِ تَبِيعًا}