Sayyiduna Salamah bin al-Akwa' (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) seated me behind him on his mount many times, passed his hand over my head, and prayed for forgiveness for me and my descendants as many times as the fingers on my hand.
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6240