How do we know that God swears by Himself in His promises?

In the passage, the angel of the Lord states, 'By myself have I sworn,' which indicates that God is making a solemn declaration that His promises are unwavering and will come to pass. This concept of swearing by Himself is significant because God has no greater authority to appeal to; thus, He guarantees the fulfillment of His word. Hebrews 6:13 references this affirmation, showing that God's promises are not merely conditional but anchored in His very nature and character. This underscores the sovereignty of God in the lives of His people and His power to bring about His divine will.