Musnad Ahmad 25:396

Abdullah said: I found in my father’s book, in his own handwriting: Mahdi ibn Ja’far al-Ramli narrated to us, al-Walid—meaning Ibn Muslim—narrated to us, from al-Hakam ibn Mus’ab, from Muhammad ibn Ali ibn Abdullah ibn Abbas, from his father, from his grandfather Abdullah ibn Abbas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever increases in seeking forgiveness, Allah will grant him relief from every worry, a way out from every distress, and will provide for him from where he does not expect."