سنن النسائي

It was narrated that 'Ikrimah said: "A man declared Zihar to his wife, then had intercourse with her before he had offered the expiation. He mentioned that to the Prophet. The Prophet (ﷺ) said to him: 'What made you do that?' He said: 'May Allah have mercy on you, O Messenger of Allah. I saw her anklets, or her calves, in the light of the moon.' The Messenger of Allah (ﷺ) said: 'Keep away from her until you have done that which Allah, the Mighty and Sublime, has commanded.'"