Leviticus 5:19

It is a trespass offering: he hath certainly trespassed against the LORD.

It is a trespass offering, and as such it stands as one of many required returns to God that set a portion of property apart as holy and demonstrated that His claim stood highest of all. The tithe was not the measure of giving but only one part of a larger required system that also included ransom for the firstborn, firstfruits of flocks and harvest, the corners of fields and dropped grain left for the poor, allowing the land to yield spontaneously for the needy every seventh year, sacrificial offerings, sin offerings, trespass offerings, remission of debts every seventh year, hospitalities, gifts to the poor, assessments on property, and special freewill offerings such as those for the tabernacle in the wilderness and the temple at Jerusalem. The required gifts were proportioned to what had been entrusted, so the larger the capital entrusted the more valuable the gift required.

The same obligation rests on Christians to give beyond the tithe proportion, including sin offerings and thank offerings. The faithful devoted about one-third of income to religious interests and the poor. Giving is to be examined at stated periods with attention to vows, recognizing that what God requires is for the giver's own good and to sustain His service.