Adam Clarke on 2 Corinthians 2:15

For we are unto God a sweet savor of Christ - The apostle still alludes to the case of a triumph; the conqueror always represented the person of Jupiter; as even the heathens supposed that God alone could give the victory: and as the punishment of death was inflicted on some of the captives, who had often rebelled and broken leagues and covenants; so others were spared, made tributaries, and often became allies. Alluding to this, the apostle says: We are a sweet savour to God - we have fulfilled his will in faithfully proclaiming the Gospel, and fighting against sin. And as he has determined that those who believe shall be saved, and those who believe not shall perish, we are equally acceptable to him though we unsuccessfully preach the Gospel to some who obstinately reject it, and so perish, as we are in preaching to others who believe, and are saved.