Adar

Terumat ma'aser is the portion that the Levite separates from the tithe he received and gives to the priest. The Levite separates a tenth of the tithe - a tithe of the tithe - and gives it to the priest as terumah. This mitzvah connects the Levite with the priest, and completes the chain of holiness from the field to the Temple. The farmer gives to the Levite, and the Levite gives to the priest, and through this chain, the produce of the land reaches its full sanctity. The Sages taught that terumat ma'aser is a mitzvah in itself, and the Levite is commanded to separate it. Without it, the tithe the Levite received is not fully sanctified.