NET
21 for no prophecy was ever borne of human impulse; rather, men carried along by the Holy Spirit spoke from God.
Darby
21 for prophecy was not ever uttered by [the] will of man, but holy men of God spake under the power of [the] Holy Spirit.
KJV
21 For the prophecy came not in old time by the will of man: but holy men of God spake [as they were] moved by the Holy Ghost.