Muwatta Imam Malik Book of Hajj, Hadith 73

Yahya related to me from Malik, from Nafi, that Abdullah ibn Umar used to say, "Someone in ihram may neither get married, nor arrange a marriage for himself or others."

وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، كَانَ يَقُولُ لاَ يَنْكِحِ الْمُحْرِمُ وَلاَ