2:12-17 A believer's triumphs are all in Christ. To him be the praise and glory of all, while the success of the gospel is a good reason for a Christian's joy and rejoicing. In ancient triumphs, abundance of perfumes and sweet odours were used; so the name and salvation of Jesus, as ointment poured out, was a sweet savour diffused in every place. Unto some, the gospel is a savour of death unto death. They reject it to their ruin. Unto others, the gospel is a savour of life unto life: as it quickened them at first when they were dead in trespasses and sins, so it makes them more lively, and will end in eternal life. Observe the awful impressions this matter made upon the apostle, and should also make upon us. The work is great, and of ourselves we have no strength at all; all our sufficiency is of God. But what we do in religion, unless it is done in sincerity, as in the sight of God, is not of God, does not come from him, and will not reach to him. May we carefully watch ourselves in this matter; and seek the testimony of our consciences, under the teaching of the Holy Spirit, that as of sincerity, so speak we in Christ and of Christ.
17. not as many—(2Co 11:18; Php 2:21). Rather, "the many," namely, the false teachers of whom he treats (tenth through twelfth chapters, especially 2Co 11:13; 1Th 2:3).
which corrupt—Greek, "adulterating, as hucksters do wine for gain" (2Co 4:2; Isa 1:22; 2Pe 2:3, "Make merchandise of you").
as of sincerity … as of God—as one speaking from (out of) sincerity, as from (that is, by the command of, and so in dependence on) God.
in Christ's—as united to Him in living membership, and doing His work (compare 2Co 12:19). The whole Gospel must be delivered such as it is, without concession to men's corruptions, and without selfish aims, if it is to be blessed with success (Ac 20:27).