Antiquities III Chapter 10,6

6. When a week of weeks has passed over after this sacrifice, (which weeks contain forty and nine days,) on the fiftieth day, which is Pentecost, but is called by the Hebrews Asartha, which signifies Pentecost, they bring to God a loaf, made of wheat flour, of two tenth deals, with leaven; and for sacrifices they bring two lambs; and when they have only presented them to God, they are made ready for supper for the priests; nor is it permitted to leave any thing of them till the day following. They also slay three bullocks for a burnt-offering, and two rams; and fourteen lambs, with two kids of the goats, for sins; nor is there anyone of the festivals but in it they offer burnt-offerings; they also allow themselves to rest on every one of them. Accordingly, the law prescribes in them all what kinds they are to sacrifice, and how they are to rest entirely, and must slay sacrifices, in order to feast upon them.