Hebrews 6:13

For when God gave his promise to Abraham, because he could swear by no greater, he sware by himself, saying,

Hebrews 3:18

and who were they, who, he sware, should not enter into his rest, but those that did not believe? so we see that they could not enter in,

Hebrews 6:17

wherefore God was willing to give the heirs of promise a stronger proof of the immutability of his counsel, by the intervention of an oath:

Treasury of Scripture Knowledge

Summary

But if ye will not hear these words, I swear by myself, saith the LORD, that this house shall become a desolation.

Bible References

I

Hebrews 3:18
and who were they, who, he sware, should not enter into his rest, but those that did not believe? so we see that they could not enter in,
Hebrews 6:13
For when God gave his promise to Abraham, because he could swear by no greater, he sware by himself, saying,