Musnad Ahmad 25:1501

Rawh ibn ‘Ubadah narrated to us, Ibn Jurayj narrated to us, he said: Yahya ibn Sa‘id informed me, from al-Qasim ibn Muhammad, from Ibn ‘Abbas: That a man came to the Messenger of Allah, may Allah bless him and grant him peace, and said: "O Messenger of Allah, I have not had relations with my wife since the *‘ifar* of the palm trees" — he said: And the *‘ifar* of the palm trees is when they are pollinated, they are left for forty days, not being watered after pollination — "then I found a man with my wife. Her husband was sallow-complexioned, thin-shanked, and straight-haired, while the one she was accused with was fleshy, tending toward blackness, and had curly, knotted hair." The Messenger of Allah, may Allah bless him and grant him peace, said: "O Allah, make it clear." Then he performed the *li‘an* (oath of imprecation) between them, and she brought forth a child who resembled the one she was accused with.