“According to Scripture, a tithe is a gift offered in support of the priests and priestly people—the Levites (cf. Num. 18:21). Not all Levites were priests…but the whole tribe of Levi was a priestly people.
Today an equivalent might be all priests and those who serve the Church: religious sisters and brothers, missionaries and groups that serve the Kingdom of God. The word tithe means literally “ten” and 10% constituted a full offering in the Bible. A tithe is also referred to as the “first fruits”: sacrificing to God the best we have to offer. In Old Testament times, this meant the best lambs or the best part of the harvest. Most of us work for money now, so the tangible fruits of our labor end up being figures in a checking account or stock holdings. The concept is the same.
A tithe serves two purposes – It supports the Church, and, more importantly, a tithe is a symbolic gesture that all we have really belongs to God. By offering back the first 10% of our income to God through the Church, we literally show that we trust Him. God the Father offered His “first fruit” – His Son – to us on the Cross, replacing the Old Testament sacrifices with His Son on the Cross and at Mass. We imitate the Father’s love by offering the best we have to offer.