Wallazeena yuzaahiroona min nisaaa'ihim summa ya'oodoona limaa qaaloo fatabreeru raqabatim min qabli any-yatamaaassaa; zaalikum too'azoona bih; wallaahu bimaa ta'maloona khabeer
And those who pronounce thihar from their wives and then [wish to] go back on what they said – then [there must be] the freeing of a slave before they touch one another. That is what you are admonished thereby; and Allah is Aware of what you do.
1 Mufti Taqi Usmani
Those who declare Zihār against their wives, then retract what they said, obligated on them is to free the neck (of a slave) before the two (spouses) touch one another. This is what you are advised, and Allah is well aware of what you do.