Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrated: When Hilal bin Umayyah accused his wife of adultery with Sharik bin al-Sahma', the Messenger of Allah (peace and blessings be upon him) said to him: "You will bring proof of what you claim, or else you will be given the prescribed punishment (of lashes)." Hilal said: By the One who sent you with the truth! I am truthful, and Allah will surely reveal my exoneration. So the verse of li'an was revealed. The Messenger of Allah (peace and blessings be upon him) called him, and the two of them performed li'an. When the fifth (testimony) remained, the Messenger of Allah (peace and blessings be upon him) said: "This (curse) makes it binding, and I wished that mercy be shown to her." Then she said: By Allah! I will not disgrace my people, and she went on (with the li'an). At this the Messenger of Allah (peace and blessings be upon him) said: "Watch her: if she gives birth to a child who is fair, with straight hair and small eyes, he is Hilal bin Umayyah's; and if she gives birth to a child who is dark, with curly hair and eyes that look as if lined with kohl, he is Sharik bin al-Sahma's." And she gave birth to a child resembling Sharik.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11833