The church needs financial support for it to discharge its duties. There are bills to be paid. There are things which must be purchased. To propagate the gospel of Jesus Christ, we will need to have money. Money is needed in the church. We cannot preach the gospel without money. So, there is a need for money in the church.
The contributions in the church are not under compulsion. There is no levy in the church. We are not compelled to bring our money. The Bible teaches us that whatever we want to give should be with a free will mind. Nobody should be made to be outside his or her own willingness.
In the Old Testament, God commanded the children of Israel to bring the tenth of their increase for the temple. That is what is known as tithe. Abraham was the one who first paid tithe when he gave one tenth of the spoilt when he returned from battle to Melchizedek.
Tithing is not a sin but God is not giving us that law again in the New Testament. In the New Testament, we are to give according to what we plan in our hearts.