Cross reference
Leviticus 23:44
44 And Moses made clear to the children of Israel the orders about the fixed feasts of the Lord.
Leviticus 21:24
24 These are the words which Moses said to Aaron and to his sons and to all the children of Israel.
Leviticus 23:1-2
1 And the Lord said to Moses,
2 Say to the children of Israel, These are the fixed feasts of the Lord, which you will keep for holy meetings: these are my feasts.
Matthew 18:20
20 For where two or three are come together in my name, there am I among them.