Thematic Bible: Being made without an oath

And this was not done without the taking of an oath [by God], (for [Levitical] priests were appointed without [God] taking [such] an oath, but Christ was appointed with an oath by God when He said to Him [Psa. 110:4], "The Lord made a vow and will not change His mind [when He said], 'You are a priest forever')." So therefore, Jesus has become the guarantee of a better Agreement [between God and mankind].