Hebrews 7:21

For although those priests became such without an oath, He had an oath form God who said to him, The Lord hath sworn and will not change, Thou art a priest forever.

Treasury of Scripture Knowledge

Summary

Lord, where are thy former lovingkindnesses, which thou swarest unto David in thy truth?

Bible References

Thou

Hebrews 7:21
For although those priests became such without an oath, He had an oath form God who said to him, The Lord hath sworn and will not change, Thou art a priest forever.