For all the promises of God in him are yea, and in him Amen, unto the glory of God by us. For all the promises of God - Had we been light, fickle, worldly-minded persons; persons who could only be bound by our engagements as far as comported with our secular interest; would God have confirmed our testimony among you? Did we not lay before you the promises of God? And did not God fulfill those promises by us - by our instrumentality, to your salvation and his own glory? God is true; therefore every promise of God is true; and consequently each must have its due fulfillment. God will not make use of trifling, worldly men, as the instruments by which he will fulfill his promises; but he has fulfilled them by us; therefore we are just and spiritual men, else God would not have used us.
In him are yea, and in him amen - All the promises which God has made to mankind are yea - true in themselves, and amen - faithfully fulfilled to them who believe in Christ Jesus. The promises are all made in reference to Christ; for it is only on the Gospel system that we can have promises of grace; for it is only on that system that we can have mercy. Therefore, the promise comes originally by Christ, and is yea; and it has its fulfillment through Christ, and is amen; and this is to the glory of God, by the preaching of the apostles.
From what the apostle says here, and the serious and solemn manner in which he vindicates himself, it appears that his enemies at Corinth had made a handle of his not coming to Corinth, according to his proposal, to defame his character, and to depreciate his ministry; but he makes use of it as a means of exalting the truth and mercy of God through Christ Jesus; and of showing that the promises of God not only come by him, but are fulfilled through him.