Leviticus 23:37
These are the feasts of the LORD, unto which ye shall be summoned: holy convocations to offer an offering on fire unto the LORD, a burnt offering and a present, a sacrifice and drink offerings, every thing in its proper time;
Leviticus 23:2
Speak unto the sons of Israel and say unto them, The feasts of the LORD, unto which ye shall make a general convocation of all the people, these shall be my feasts.
Leviticus 23:4
These are the feasts of the LORD, the holy convocations, which ye shall proclaim in their appointed times.
Deuteronomy 16:16-17
Three times each year shall all thy males appear before the LORD thy God in the place which he shall choose: in the solemn feast of unleavened bread and in the solemn feast of weeks and in the solemn feast of the tabernacles. And they shall not appear before the LORD empty,
Ecclesiastes 3:1
For all things there is a season, and every will under the heaven has its time determined.