Sahih Muslim Book 8, Hadith Number 3278.

Chapter: Mubrim (one who is in the state of Ihram) is forbidden to marry and the disapproval of giving the proposal (in this state).

Nubaih b. Wahb reported that ‘Umar b. Ubaidullah intended to marry Talha b. ‘Umar with the daughter of Shaiba b. Jubair; so he sent a messenger to Aban b. Uthman to attend the marriage, and he was at that time the Amir of Hajj. Aban said: I heard ‘Uthman b. ‘Affan say that Allah’s Messenger (May peace be upon him) had stated: A Muhrim must neither marry himself, nor arrange the marriage of another one, nor should he make the proposal of marriage.