Exodus 23:15-17

Young's Literal Translation

¹⁵ the Feast of Unleavened things thou dost keep; seven days thou dost eat unleavened things, as I have commanded thee, at the time appointed [in] the month of Abib; for in it thou hast come forth out of Egypt, and ye do not appear [in] My presence empty;

¹⁶ and the Feast of Harvest, the first fruits of thy works which thou sowest in the field; and the Feast of the In-Gathering, in the outgoing of the year, in thy gathering thy works out of the field.

¹⁷ `Three times in a year do all thy males appear before the face of the Lord Jehovah.