Adar

Ma'aser rishon is the first tithe, separated from all agricultural produce and given to the Levite. After separating the terumah for the priest, the farmer separates a tenth of the remaining produce as the first tithe. The Levite, who has no portion in the land, receives this tithe as his inheritance. The Levite in turn separates a portion of the tithe - terumat ma'aser - and gives it to the priest. This mitzvah creates a chain of holiness: the farmer separates terumah for the priest, the first tithe for the Levite, and the Levite separates a portion for the priest. Through this chain, the produce of the land carries holiness from the field to the Temple.