Surah Al-Mujadilah (The Pleading Woman), Verse 3

وَالَّذِیْنَ یُظٰهِرُوْنَ مِنْ نِّسَآىِٕهِمْ ثُمَّ یَعُوْدُوْنَ لِمَا قَالُوْا فَتَحْرِیْرُ رَقَبَةٍ مِّنْ قَبْلِ اَنْ یَّتَمَآسَّا ذٰلِكُمْ تُوْعَظُوْنَ بِهٖ وَاللّٰهُ بِمَا تَعْمَلُوْنَ خَبِیْرٌ ۟

Wallazeena yuzaahiroona min nisaaa'ihim summa ya'oodoona limaa qaaloo fatahreeru raqabatim min qabli any-yatamaaassaa; zaalikum too'azoona bih; wallaahu bimaa ta'maloona khabeer

“But those who divorce their wives by Zihar, then wish to go back on the words they uttered,- (It is ordained that such a one) should free a slave before they touch each other: Thus are ye admonished to perform: and Allah is well-acquainted with (all) that ye do.”

Quran 58:3 (Yusuf Ali Translation)