What is the ruling of Islamic law regarding the occurrence of the forbidden between a father and his married daughter by mistake in the dark? Are they considered sinful? What is the expiation for this sin? Must the daughter veil herself from her father after that? Does this act necessitate the divorce of the mother? Is it permissible to keep the matter a secret from the husband, the mother, and the rest of the family?

If the matter occurred by mistake, there is no sin upon either of you, because error is forgiven. This action does not necessitate your veiling from him, nor does it cause your mother to become forbidden to him. The majority of scholars hold that direct contact (mubasharah) without penetration does not establish prohibition, just as the sanctity of marriage by intercourse does not establish prohibition. Therefore, keep the matter secret from your husband and others.