17 When I therefore was thus minded, did I show fickleness? or the things that I purpose, do I purpose according to the flesh, that with me there should be the yea yea and the nay nay? 18 But as God is faithful, our word toward you is not yea and nay. 19 For the Son of God, Jesus Christ, who was preached among you by us, [even] by me and Silvanus and Timothy, was not yea and nay, but in him is yea. 20 For how many soever be the promises of God, in him is the yea: wherefore also through him is the Amen, unto the glory of God through us.
Matthew Henry's Commentary on 2 Corinthians 1:17-20
Commentary on 2 Corinthians 1:15-24
(Read 2 Corinthians 1:15-24)
The apostle clears himself from the charge of levity and inconstancy, in not coming to Corinth. Good men should be careful to keep the reputation of sincerity and constancy; they should not resolve, but on careful thought; and they will not change unless for weighty reasons. Nothing can render God's promises more certain: his giving them through Christ, assures us they are his promises; as the wonders God wrought in the life, resurrection, and ascension of his Son, confirm faith. The Holy Spirit makes Christians firm in the faith of the gospel: the quickening of the Spirit is an earnest of everlasting life; and the comforts of the Spirit are an earnest of everlasting joy. The apostle desired to spare the blame he feared would be unavoidable, if he had gone to Corinth before he learned what effect his former letter produced. Our strength and ability are owing to faith; and our comfort and joy must flow from faith. The holy tempers and gracious fruits which attend faith, secure from delusion in so important a matter.