How should a Muslim deal with those who worship at graves?

Question:
He says: I am from India, and I have neighbors who circumambulate graves and prostrate at graves, and there are many of them in our village. What is my position regarding these people? And is it permissible for me to deal with them and speak to them, while I fear their harm, and they are Muslims?

Answer:
You must advise them and explain to them. These people are ignorant. Advise them, preach to them, and distribute books on tawhid (the oneness of Allah) and treatises on tawhid, so that perhaps Allah will guide them. As for dealing with them in permissible matters, dealing with them in permissible things, there is no harm in buying and selling and...