Hebrews 6:13

For when God made a promise to Abraham, since he had no one greater by whom to swear, he swore by himself,

Hebrews 3:18

And to whom did he swear that they would never enter his rest, but to those who were disobedient?

Hebrews 6:18

so that, by two unchangeable things in which it is impossible for God to lie, we who have taken refuge would have strong encouragement to take hold of the hope set before us.

Treasury of Scripture Knowledge

Summary

Therefore hear ye the word of the LORD, all Judah that dwell in the land of Egypt; Behold, I have sworn by my great name, saith the LORD, that my name shall no more be named in the mouth of any man of Judah in all the land of Egypt, saying, The Lord GOD liveth.

I have sworn

Bible References

I have sworn

Hebrews 3:18
And to whom did he swear that they would never enter his rest, but to those who were disobedient?
Hebrews 6:13
For when God made a promise to Abraham, since he had no one greater by whom to swear, he swore by himself,