Wherein God, willing more abundantly to shew unto the heirs of promise the immutability of his counsel, confirmed it by an oath:
Ver. 17. God willing more abundantly] His word is sufficient, yet tendering our infirmity he hath bound it with an oath, and set to his seal. His word cannot be made more true, but yet more credible. Now two things make a thing more credible: 1. The quality of the person speaking; 2. The manner of the speech. If God do not simply speak, but solemnly swear, and seal to us remission of sins, and adoption of sons by the broad seal of the sacraments, and by the privy seal of his Spirit, should we not rest assured?