“It is unlawful for a Muslim husband to prevent his wife from visiting her Christian parents because, as a Muslim, she is commanded to be devoted and of good company to them. Indeed, this matter was mentioned immediately after the command to worship Allah Almighty alone and none other. Almighty Allah says: "And your Lord has decreed that you worship none but him, and that you be dutiful to your parents." (al-Isra': 23) This verse clearly affirms that the greatest right of human beings after the right of Allah is that of the parents.
Islam did not prevent Muslims from being dutiful to their non-Muslim parents even if they practiced polytheism (shirk). Islam did not prevent Muslims from doing so even if the parents tried to force their children to leave Islam and enter into ignorance and shirk. Allah says: "And We have enjoined on man to be dutiful and good to his parents. His mother bore him in weakness and hardship upon weakness and hardship, and his weaning is in two years - give thanks to Me and to your parents; unto Me is the final destination. But if they strive with you to make you join in worship with Me others that of which you have no knowledge, then obey them not, but behave with them in the world kindly…" (Luqman: 13-14) In this verse, Allah orders that their call to polytheism be rejected, but also orders that one behave kindly with his or her parents at all times.
It is also narrated that Asma', the daughter of Abu Bakr, came to the Prophet Muhammad (peace and blessings be upon him) after the Treaty of Hudaybiyyah and asked him, “O Messenger of Allah! My mother has come to visit me and she is a mushrik (polytheist); shall I make contact with her, be kind to her and give her some money?” He (peace and blessings be upon him) said: "Yes. Be dutiful to your mother." (Reported by al-Bukhari and Muslim) Some scholars said that this incident was the reason for the revelation of the Qur'anic verse: "Allah does not forbid you to deal justly and kindly with those who fought not against you on account of religion and did not drive you out of your homes. Verily Allah loves those who deal with equity." (Al-Mumtahanah: 8)
Islam also decreed that the non-Muslim parents actually receive a bequest (by will) from their Muslim children, as appears from the verse: "It is prescribed for you, when death approaches any of you, if he leaves wealth, that he make a bequest to parents and next of kin, according to reasonable manners. This is a duty upon the pious." (Al-Baqarah: 180)
It is well known that a bequest cannot be made for the Muslim parents, because they are actual inheritors and an inheritor must not be left a bequest. Therefore, the reference in this verse is to the non-Muslim parents and next of kin, because their status as non-Muslims does not annul their status nor their rights as parents or relatives. Allah Almighty says: "And fear Allah through Whom you demand your mutual rights and do not sever the relations of the wombs." (An-Nisa': 1)
Islam considered relationship by marriages one of two natural forms of relationship between people, the other being natural blood relationships. Allah says: "And it is He Who created man from water, and has appointed for him kindred by blood and kindred by marriage…" (Al-Furqan: 54)
Thus, it would be unlawful to reject or disregard such an instinctive relationship. It is upon the husband to strengthen his ties with his wife's relatives, particularly her parents. He must do his best to be good to them and to become close to them, even if they are non-Muslims, as this will make him in a position to bring them closer to Islam. Indeed, Islam spread by virtue of good manners and dealings with others. A husband must never prevent his wife from being good to her parents, whether they are Muslims or otherwise. In fact, he must encourage her to visit them and should accompany her as well as invite them to visit his house, as all this fulfils the requirements of kinship decreed by Allah. The husband must also remember that his wife's parents are his children's grandparents, and her brothers and sisters are their uncles and aunts, and that all of them have rights of kinship.
We often see the effects of good manners and behavior on others. Indeed, many embraced Islam simply because of the beautiful way in which true Muslims treated them. Unfortunately, we also see how ill-treatment and bad manners cause people to hate Islam and Muslims. Great reward will come to him or her who causes good and prevents evil, and great punishment will come to him or her who causes evil and prevents good.” Council for Fatwa and Research