Matthew 18:17
18:17The word ‘church’ means a group of Christians. They meet together because they are obeying Jesus. It does not mean the building where they meet.
18:17This does not mean that we should only be friends with other Christians. We can be friends with other people too. But perhaps a person says that he follows Jesus. But he does not obey Jesus. Then we should not be a special friend of that person.