It was narrated in a saheeh hadeeth that the Prophet (peace and blessings of Allaah be upon him) said:
“The prayer of Dhu’l-Noon (Yoonus) which he said when he was in the belly of the whale:
‘Laa ilaaha illa anta, subhaanaka, inni kuntu min al-zaalimeen
([none has the right to be worshipped but You (O Allaah)], Glorified (and Exalted) be You [above all that (evil) they associate with You]! Truly, I have been of the wrongdoers.’
No Muslim recites this du’aa’ concerning any matter but Allaah will answer him.”
Narrated by al-Tirmidhi and classed as saheeh in Saheeh al-Jaami’, 3383.
Jazak Allah Khayr