This certainty is not a bare conjectural and probable persuasion, grounded upon a fallible hope;[a] but an infallible assurance of faith, founded upon the divine truth of the promises of salvation,[b] the inward evidence of those graces unto which these promises are made,[c] the testimony of the Spirit of adoption witnessing with our spirits that we are the children of God:[d] which Spirit is the earnest of our inheritance, whereby we are sealed to the day of redemption.[e]