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.