Leviticus 23:2

23:2 “Speak to the Israelites and tell them, ‘These are the Lord’s appointed times which you must proclaim as holy assemblies – my appointed times:

Leviticus 23:4

The Festival of Passover and Unleavened Bread

23:4 “‘These are the Lord’s appointed times, holy assemblies, which you must proclaim at their appointed time.

Deuteronomy 16:16-17

16:16 Three times a year all your males must appear before the Lord your God in the place he chooses for the Festival of Unleavened Bread, the Festival of Weeks, and the Festival of Temporary Shelters; and they must not appear before him empty-handed. 16:17 Every one of you must give as you are able, according to the blessing of the Lord your God that he has given you.