Musnad Ahmad 163:1

Al-Hakam ibn Nafi’ narrated to us, he said: Isma’il ibn ‘Ayyash narrated to us, from Salim ibn ‘Abdullah, from ‘Abdullah ibn Muhammad ibn ‘Aqil, he said: ‘Aqil ibn Abi Talib got married, so he came out to us, and we said: "With concord and sons." He said: "Desist! Do not say that, for the Prophet, peace and blessings of Allah be upon him, has forbidden us from that, and he said: 'Say: May Allah bless for you, and bless upon you, and bless for you in her.'"