Oracular

1810, Sir Walter Scott, Lady of the LakeIn some of the Hebrides they attributed the same oracular power to a large black stone by the sea-shore, which they approached with certain solemnities, and considered the first fancy which came into their own minds, after they did so, to be the undoubted dictate of the tutelar deity of the stone, and, as such, to be, if possible, punctually complied with.
2006, Lisa Hill, The Passionate Society: the social, political and moral thought of Adam FergusonFerguson's sin consisted in his oracular 'unmasking' of a 'second-rate sort of society, full of second rate citizens, pursuing comparatively worthless objects.'

1844, William Makepeace Thackeray, Barry LyndonMy Lord Chatham, whose wisdom his party in those days used to call superhuman, raised his oracular voice in the House of Peers against the American contest;

1754, Horace Walpole, letter to John ChuteNothing offended me but that lisping Miss Haughton, whose every speech is inarticulately oracular.
1895, Andrew Dickson White, History of the Warfare of Science with Theology in ChristendomThis utterance was admirably oracular, being susceptible of cogent quotation by both sides...