'Guarantee' in the Bible

And God said, "This is the guarantee of the covenant I am making with you and every living creature with you, a covenant for all subsequent generations:

I will place my rainbow in the clouds, and it will become a guarantee of the covenant between me and the earth.

So God said to Noah, "This is the guarantee of the covenant that I am confirming between me and all living things that are on the earth."

Guarantee the welfare of your servant! Do not let the arrogant oppress me!

accordingly Jesus has become the guarantee of a better covenant.