Jesus is guarantee of a better covenant

Hebrews 7:18 The former regulation is set aside because it was weak and useless 19 (for the law made nothing perfect), and a better hope is introduced, by which we draw near to God. 20 And it was not without an oath! Others became priests without any oath, 21 but he became a priest with an oath when God said to him: “The Lord has sworn and will not change his mind: ‘You are a priest forever.’ ” 22 Because of this oath, Jesus has become the guarantee of a better covenant. - (NIV84)Hebrews 10:11 Day after day every priest stands and performs his religious duties; again and again he offers the same sacrifices, which can never take away sins. 12 But when this priest had offered for all time one sacrifice for sins, he sat down at the right hand of God. - (NIV84)