Musnad Ahmad 1165:18

Bahz and 'Affan narrated to us, they said: Hammam narrated to us, he said: Qatadah narrated to us, from Abu al-Khalil, from 'Abdullah ibn al-Harith, from Umm al-Fadl bint al-Harith, she said: A man asked the Prophet, may Allah bless him and grant him peace: "Does one suckling make [marriage] unlawful?" The Prophet, may Allah bless him and grant him peace, said: "No." And 'Affan said: The Prophet, may Allah bless him and grant him peace, was asked, and he mentioned it.