Guarantor
There is no guarantee
Within me
Of righteousness or future glory,
No guarantee
Of how the story
Will resolve. Yet in You in see,
Only in Your pure blood,
O my God,
Does the story have its certainty,
Its final good
And this perfect plea:
Sins pardoned, frailty understood.
The Consolations of Writing 
Hebrews 7:22 in the ESV uses that word where it says:” Jesus is the guarantor of a better covenant.”
Thank You Lord. Amen.
Thanks for that. I hadn’t realised that the ESV uses that exact word! I actually had Hebrews 12:23-24 in my head when I wrote the poem, so it’s wonderful to know that another Hebrews verse confirms the idea.