For (gar). The reason for the previous statement that no prophet starts a prophecy himself. He is not a self-starter.
Came (ēnechthē). First aorist passive indicative of pherō (2Pe 1:17.).
By the will of man (thelēmati anthrōpou). Instrumental case of thelēma. Prophecy is of divine origin, not of one’s private origination (idias epiluseōs).
Moved by the Holy Ghost (hupo pneumatos hagiou pheromenoi). Present passive participle of pherō, moved from time to time. There they “spoke from God.” Peter is not here warning against personal interpretation of prophecy as the Roman Catholics say, but against the folly of upstart prophets with no impulse from God.