Fear God - the forerunner to embracing the love of God manifested in the Gospel. Repentance accompanies faith.
give glory to him - and not to the beast (compare Rev 13:4; Jer 13:16).
the hour of his judgment - “The hour” implies the definite time. “Judgment,” not the general judgment, but that up on Babylon, the beast, and his worshippers (Rev 14:8-12).
worship him that made heaven - not Antichrist (compare Act 14:15).
sea ... fountains - distinguished also in Rev 8:8, Rev 8:10.