Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will shew you things to come. (John 16:13)
See on chs. 14:26; 16:12. “Truth” is here used primarily in its theological sense (see on ch. 8:32). However, it is also true that all right scientific discoveries and inventions have their source in God (see CT 277).
Not speak of himself.
Jesus declared the same concerning Himself (chs. 12:49; 14:10). The ultimate source of authority was God.
Things to come.
Jesus had revealed things to come (Matt. 24; etc.). But more light concerning the future was to be given. The prophecies of Revelation are an outstanding example of how this was fulfilled. Concerning the messages to the churches John declared, “Let him hear what the Spirit saith unto the churches” (Rev. 2:7, 11; etc.).