No servant has ever said it without Allah removing his grief and replacing it with joy

Sayyiduna Ibn Mas’ud radiAllahu anhu narrates that the beloved Messenger of Allah ﷺ said: “Whoever is overwhelmed with worry should say: 

Allahumma inni ‘abduka wabnu ‘abdika wabnu amatika wa fi qabdatika nasiati biyadika madin fiyya hukmuka ‘adlun fiyya qada’uka As’aluka bikulli ismin huwa laka sammayta bihi nafsaka aw anzaltahu fi kitabika aw ‘allamtahu ahadan min khalqika aw alhamtahu ‘ibadaka Aw ista’tharta bihi fi maknun al-ghaybi ‘indaka an taj’ala al-Qur’ana rabi’a qalbi wa jila’a hammi wa ghammi

‘O Allah, I am Your servant, the son of Your servant, the son of Your maidservant; my forelock is in Your hand, Your command over me is forever executed, and Your decree over me is just. I ask You by every name belonging to You which You have named Yourself with, or revealed in Your Book, or taught to any of Your creation, or have preserved in the knowledge of the unseen with You, that You make the Qur’an the life of my heart and the light of my chest, the banisher of my grief and the reliever of my distress.’ 

No servant has ever said it without Allah removing his grief and replacing it with joy.” 

Ref: Mishkat al Masabih, chapter on supplications, Book 9, Hadith 221