سورة Al-Mujadilah ( She That Disputeth ) - الآية 3

And those who make unlawful to them (their wives) (by Az-Zihar) and wish to free themselves from what they uttered, (the penalty) in that case (is) the freeing of a slave before they touch each other. That is an admonition to you (so that you may not return to such an ill thing). And Allah is All-Aware of what you do.