Narrated Ibn 'Abbas:
"The Messenger of Allah (ﷺ) said to Al-'Abbas: 'On the night of Monday, come to me, you and your offspring, so that I may supplicate for them with a supplication that Allah will benefit you and your children by.' So he went, and we went with at night, so he (ﷺ) covered us in a Kisah (shawl), then said: 'O Allah, forgive Al-'Abbas and his offspring, for what is open and what is secret, with a forgiveness that does not leave any sins. O Allah! Take care of him concerning the affair of his offspring.'"
English reference: Vol. 1, Book 46, Hadith 3762
Arabic reference: Book 49, Hadith 4129