Shaikh Saduq, through his chain of transmitters, quotes from Safiyyah bint Abdul Muttalib, that she said: When Imam Husayn (a.s.) was born, I was attending to his mother. The Holy Prophet (S) came to me and said,
“O Aunt! Bring my son to me.”
I replied that I had not yet purified him. He replied,
“Will you purify him? Rather Allah, the Exalted, has cleansed and purified him.”
In another tradition it is related that Safiyyah says that she then gave the child to the Prophet who placed his tongue in his mouth, and Imam Husayn (a.s.) started licking it. Safiyyah says that I strongly perceive that the Prophet did not give him anything else except milk and honey. She says that then the child urinated and the Prophet planted a kiss in the centre of his eyes and wept, then handing him over to me said,
“O my dear son! May Allah curse the people who will kill you”,
and he repeated it thrice. I asked, “May my parents be your ransom! Who will kill him”? and he replied,
“The oppressive group to emerge from among the Bani Umayyah.”
Reference : Nafasul Mahmoom – Shaikh abbas Qummi (r.a.)