Exodus 23:17
Three items in the year all your males shall appear before the LORD God.
Torrey's Topical Textbook—AKJV

Deuteronomy 16:16
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 tabernacles: and they shall not appear before the LORD empty:
Torrey's Topical Textbook—AKJV