Musnad Ahmad 3689
Musnad of Abdullah bin Mas'ood
It was narrated that 'Abdullah (رضي الله عنه) said: The Messenger of Allah (ﷺ) said: "There is no-one who is afflicted by distress and gries, and says: ‘O Allah, I am Your slave, son of Your slave, 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 You taught to any of Your creation, or You revealed in Your Book or You 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 breast, and a departure for my sorrow and a release for my anxiety,' but Allah will take away his distress and grief, and replace it with joy.” It was said:O Messenger of Allah, should we not learn it (by heart)? He said: “Of course. Everyone who hears it should learn it (by heart).”