Does a divorce take effect if the husband said to his wife during her postpartum period (nifas): "If you do not return tomorrow, then you are divorced," and she did not return, and then the husband reconciled with her inwardly after the 'iddah period expired, and she returned to him years later and he cohabited with her?

If you verbally take back your wife before the expiration of her iddah (waiting period), then the revocation is valid. She remains your wife under your marital authority, and cohabiting with her is permissible. Her knowledge or consent is not a condition.

However, if you intended the revocation inwardly without verbalizing it, the majority of scholars do not consider the revocation to have occurred. In contrast, the Malikis hold that it does occur by intention, in terms of religious obligation (diyanatan), but it is not legally ruled as such based solely on intention.

The preponderant view is that of the majority. Therefore, if no revocation occurred from you except for the intention, you must refrain from cohabiting with the woman until the marriage contract is renewed, because a divorced woman becomes a stranger (non-mahram) after the iddah.