Tithing means returning a portion of our increase to the Lord, honoring Him as the Provider of all things. As one-seventh of our time (the Sabbath) belongs to God (Exodus 20:8-11), so does one tenth of all material things we acquire. We tithe because God commanded us to do so. It is part of the covenant between God and His people. JTL25 5.1
Tithing is a beautiful system of equity. The proportional claim on the rich and on the poor reminds us that all can return to God a tithe in response to what He has lent us to manage. JTL25 5.2