Old English godspel "gospel, glad tidings announced by Jesus; one of the four gospels," from god "good" (see good) + spel "story, message" (see spell (n.)); translation of Latin bona adnuntiatio, itself a translation of Greek euangelion "reward for bringing good news."
The first element of the Old English word had a long "o," but it shifted under mistaken association with God. The word passed early from English to continental Germanic languages in forms that clearly indicate the first element had shifted to "God," e.g. Old Saxon godspell, Old High German gotspell, Old Norse goðspiall. Used of anything as true as the Gospel from mid-13c. Gospel-gossip was Addison's word ("Spectator," 1711) for "one who is always talking of sermons, texts, etc."