"Oh, [by] grace how great a debtor | Daily [God's] constrained to be"

"God is faithful and has put himself in our debt not because we have given him anything but because he has promised us so much. Yet even promising was not enough for him. He wanted to be bound in writing as well [(fidelis deus qui se nostrum debitorem fecit, non aliquid a nobis accipiendo, sed tanta nobis promittendo. parum erat promissio, etiam scripto se teneri uoluit)]. . . .  [Indeed, h]e was . . . not content to provide us with a written guarantee of his promises to help us believe in him. He even appointed a mediator to establish his good faith: not some nobleman, nor an angel, nor an archangel, but his only Son."  Etc.

     St. Augustine, Ennar. in Ps. 109.1-2, WSA III/19, trans. Boulding & Ramsey (2003), 261.  =CCL 40, p. 1601, ll. 11 ff.