Deuteronomy 6:13
You shall fear the LORD your God, and serve him, and shall swear by his name.
Torrey's Topical Textbook—AKJV

Deuteronomy 10:20
You shall fear the LORD your God; him shall you serve, and to him shall you hold, and swear by his name.
Torrey's Topical Textbook—AKJV

Isaiah 65:16
That he who blesses himself in the earth shall bless himself in the God of truth; and he that swears in the earth shall swear by the God of truth; because the former troubles are forgotten, and because they are hid from my eyes.
Torrey's Topical Textbook—AKJV