Leviticus 23:37
"'These are the appointed feasts of the LORD, which you shall proclaim to be holy convocations, to offer an offering made by fire to the LORD, a burnt offering, and a meal offering, a sacrifice, and drink offerings, each on its own day;
Leviticus 23:2
"Speak to the children of Israel, and tell them, 'The set feasts of the LORD, which you shall proclaim to be holy convocations, even these are my set feasts.
Leviticus 23:4
"'These are the set feasts of the LORD, even holy convocations, which you shall proclaim in their appointed season.
Deuteronomy 16:16-17
Three times in a year shall all your males appear before the LORD your God in the place which he shall choose: in the feast of unleavened bread, and in the feast of weeks, and in the feast of tents; and they shall not appear before the LORD empty:
Ecclesiastes 3:1
For everything there is a season, and a time for every purpose under heaven: