Paying of tithes was discussed in the old testament. God said to Israel to give ten percent of what they worked to the poor and priest to support them. Abraham and Jacob in the bible gave tithes to God to say thank you for what He has been doing for them. It means that tithing is part of the law of God which he gave us.
In the time of Jesus Christ in the old testament, believers are not asked to pay the same way as the old testament. The bible encourages christians to give freely whatever that comes from their heart. As a good Christian we're expected to support the works of God, in church building. Giving is something we do as a free will, not because we're pressured to do it. Tithe is still in the new testament and we have to support what we can.