I know some Muslims who have been invited to one of their evangelical Christian friend's weddings, and there will surely be a lot of singing and worshipping of Jesus Christ as lord and savior. Is it acceptable for a Muslim to attend such a wedding ceremony, and is it acceptable to sing songs that go against the teachings of Islam as a courtesy to Christian friends (or, for that matter, friends of other religions)?
There is no objection in Islamic Sharia for a Muslim to accept the invitation of a Christian to attend a wedding ceremony in the church provided there are no Munkarat (all evil acts and things) such as: drinking alcohol, singing, statues and performing forms of worship that are not for Allah. If such evil acts or things are present in the church then, it becomes unlawful to go there. Abdel Razak reported from Aslam (the servant of Umar ) who said: 'When Umar (Radiya Allahu Anhu) came to Al Sham, a top ranking Christian man made some food for him. He said to him: 'I would like you to do me a favor to visit me and eat with me'. Umar (Radiya Allahu Anhu) replied: 'We do not enter your churches because of the pictures in them' .