Quran 4:20 — Women (Al-Nesa')

If you wish to marry another wife, in place of your present wife, and you had given any of them a great deal, you shall not take back anything you had given her. Would you take it fraudulently, maliciously, and sinfully?

[4:19] O you who believe, it is not lawful for you to inherit what the women leave behind, against their will. You shall not force them to give up anything you had given them, unless they commit a proven adultery. You shall treat them nicely. If you dislike them, you may dislike something wherein GOD has placed a lot of good.

[4:21] How could you take it back, after you have been intimate with each other, and they had taken from you a solemn pledge?