[T]he Son of God, having been constituted by the Father as Mediator of the covenant, the guarantor on two counts: 1) He shall satisfy for the sins of all those whom the Father has given him (John 17) and he decreed from eternity to adopt them into sonship wrought Christ (Ephesians 1); 2) He shall also bring to pass that they, being planted in him, shall enjoy peace of conscience and be renewed daily in the image of God.

— Caspar Olevianus, De substantia foederis gratuiti inter deum et electos (1585), 1.2.1 in R. Scott Clark, Caspar Olevian and the Substance of the Covenant (p 178)