I just joined an interfaith group, because the local church sponsored some Muslim Somali refugee family of 5 females (mother plus 4 daughters) and they also wanted some Muslims to help out.
The principle in the relationship between Muslims and non-Muslims is coexistence. Muslims living in non-Muslim countries have to engage in their communities while observing their Muslim identity. It is legally impermissible for Muslims to share non-Muslims in anything that violates the fundamentals of Islamic law. Rather, it is permissible for Muslims to speak kindly and participate with non-Muslims in a manner that does not contradict the commands of Allah and His Messenger (peace and blessings be upon him).
There is no doubt that maintaining ties with non-Muslims by exchanging visits, offering condolences and good wishes, exchanging gifts and the like are from among kind treatment. This is considered one of the ways towards calling to the religion of Allah through noble manners.
Allah the Almighty commands us to speak kind words to everyone alike. He says, Speak fair to people. (Al-Baqarah 2:83) Allah also commands us to always be kind to others. He says, Allah commands justice and the doing of good. (An-Nahl, 90)
Allah does not forbid us from maintaining good ties with non-Muslims, exchanging gifts or other acts of kind treatment. Allah the Almighty says, Allah forbids you not, with regard to those who fight you not for (your) faith nor derive you out of your homes from dealing kindly and justly with them: for Allah loves those who are just. (Al-Mumtahana,
All of such good actions must be carried out while observing one’s Muslim identity.
There is no legal objection to visiting a church with the purpose of advocating and introducing Islam or offering compliments on certain occasion within the limits of the above mentioned. Likewise, it is permissible to perform prayers inside the church if its time entered while you are therein and after taking the consent of those in charge.
As for reading, studying and discussing the bible, it must be done by specialized scholars who are well versed in points of doubts and possessing the tools of understating interfaith dialogue.