What is the ruling on a man marrying a second wife without the knowledge of his first wife, what are his duties towards his first family, what sins might the recently married Muslim couple have committed in this situation, and what should they do?

Firstly, Islam obliterates the sins that preceded it. Thus, whoever embraces Islam, Allah forgives him for what he committed before his conversion, based on the Almighty's saying: (Say to those who disbelieve, if they cease, what has passed will be forgiven them) and according to the Prophet's (peace be upon him) saying: (Islam obliterates what was before it).

Secondly, illicit relationships before marriage are a sin. If they occurred before embracing Islam, they are forgiven by Islam. If they occurred after embracing Islam, repentance for them becomes obligatory, and Allah accepts repentance from His servants.

Thirdly, there is no sin in marrying a second wife if the man is able to be just, and it is not obligatory to inform the first wife.

Fourthly, the man must provide for his two children and his first wife, and strive to guide them to Islam, especially the young children who are considered Muslims following the Islam of one of their parents. He must teach them the rulings of Islam. He must also strive to bring his young children or continue to guide them to prevent their deviation. We urge both spouses to learn the rulings of Islam and apply them.