A.T. Robertson Commentary Revelation 16:9

"And men were scorched men with great heat: and they blasphemed the name of God who hath the power over these plagues; and they repented not to give him glory." — Revelation 16:9 (ASV)

Were scorched (εκαυματισθησαν). First aorist passive indicative of same verb.

With great heat (καυμα μεγα). Cognate accusative retained with the passive verb. Old word (from καιω to burn), in N.T. only 7:16 and here. For blaspheming the name of God see 13:6; James 2:7; Romans 2:24; 1 Timothy 6:1. They blamed God for the plagues.

They repented not (ου μετενοησαν). This solemn negative aorist of μετανοεω is a refrain like a funeral dirge (9:20f.; 16:11). In 11:13 some did repent because of the earthquake. Even deserved punishment may harden the heart.

To give him glory (δουνα αυτω δοξαν). Second aorist active infinitive of διδωμ, almost result. For the phrase see 11:13; 14:7; 19:7.