Exodus 23:14

23:14 “Three times in the year you must make a pilgrim feast to me.

Exodus 23:17

23:17 At three times in the year all your males will appear before the Lord God.

Deuteronomy 16:16

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.

Psalms 84:7

84:7 They are sustained as they travel along;

each one appears before God in Zion.