Sahih Muslim Book 8, Hadith Number 3331.

Chapter: Pertaining to the marriage of Zainab bint Jahsh with the Holy Prophet (May peace be upon him) and verses pertaining to purdah veil).

Anas (Allah be pleased with him) reported: I did not see Allah’s Messenger (May peace be upon him) giving a wedding feast (on the marriage) of any one (of his wives) as he did in the case of (his marriage with) Zainab, for then he sacrificed a goat (on this occasion).