“Wherein God, willing more abundantly to shew unto the heirs of promise the immutability of his counsel, confirmed it by an oath: that by two immutable things, in which it was impossible for God to lie, we might have a strong consolation, who have fled for refuge to lay hold upon the hope set before us:”
Hebrews 6:17-18 KJV,https://bible.com/bible/1/heb.6.17-18.KJV