But know this first of all, that no prophecy of Scripture is a matter of one’s own interpretation, for no prophecy was ever made by an act of human will, but men moved by the Holy Spirit spoke from God. (1:20–21)
False prophets spoke of their own things, from their own ideas, but no true message from God ever arose from a human interpretation. Interpretation (epiluseos) is an unfortunate translation because in English it indicates how one understands Scripture, whereas the Greek noun is a genitive, indicating source. Thus Peter is not referring to the explanation of the Scripture, but to its origin. The next statement in verse 21, for no prophecy was ever made by an act of human will, but (alla, “just the opposite,” “quite the contrary”) men moved by the Holy Spirit spoke from God, further supports the point of source. What human beings might think or want has absolutely nothing to do with divine prophecy. (See John MacArthur, 1 Peter, MacArthur New Testament Commentary [Chicago: Moody, 2004, 51–57].)
Moved (pheromenoi) is a present passive participle that means “continually carried,” or “borne along.” Luke twice used this verb (Acts 27:15, 17) to describe how the wind blows a sailing ship across the waters. For Peter, it was as if the writers of Scripture raised their spiritual sails and allowed the Spirit to fill them with His powerful breath of revelation as they penned its divine words (cf. Luke 1:70). When Jeremiah said, “The word of the Lord came to me saying” (Jer. 1:4), he spoke for all the Old Testament writers and, by extension, all the New Testament writers who followed them. The only one who knows the mind of God is the Spirit of God (1 Cor. 2:10–13; cf. John 15:26; Rom. 8:27; 11:34; cf. John 3:8), so only He could have inspired the Scripture.
If believers are going to stand against the errors of false teachers, they must seek to know, accept, and obey the totality of Scripture, even as the apostle Paul did in testifying before the Roman governor Felix, “But this I admit to you, that according to the Way which they [the Jews] call a sect I do serve the God of our fathers, believing everything that is in accordance with the Law and that is written in the Prophets” (Acts 24:14, emphasis added).