What is the context?
The eyewitness testimony is joined with the word of the prophets, described as confirmed beyond doubt. The readers do well to attend to it as they would to a lamp in a dark place. The image gives them a reason to keep listening while they await the dawn.
Peter then addresses the source of scriptural prophecy. The word translated interpretation concerns explanation; the next sentence connects the point with origin. Prophecy was not brought forth by human will. People spoke from God as His Spirit carried them.
The word behind carried along can describe being moved or prompted. Here the Holy Spirit supplies that direction. Human speakers are present, but the message is not presented as their own invention.
How is this passage commonly understood?
Calvin and Wesley both prefer to read verses 20–21 in terms of prophecy’s origin in God. The Reformed Westminster Confession, 1.4, grounds Scripture’s authority in God as its author, and the Catholic Catechism, 105–106, affirms the Spirit’s inspiration through genuine human authors.
The dawn and morning-star image has different readings. Calvin looks toward the fuller sight of God beyond the present life. Wesley connects it with the light of the Gospel and Christ being revealed in the heart. Both treat the prophetic message as a light that directs believers toward Christ.
Where does this fit in God's plan?
In Luke 24:25–27, 44–49, the risen Jesus explains the Scriptures in relation to His suffering, resurrection and the proclamation of forgiveness to the nations. The prophetic word belongs to that unfolding saving purpose.
Its role is therefore more than supplying isolated predictions. It directs people to the Christ through whom God has acted and to the message His witnesses are to carry.
What is our position?
Our study Is the Bible the Inerrant Word of God? understands this passage as describing Scripture’s origin in God: His Spirit carried the human speakers as they spoke from Him. The study applies inerrancy to the original texts as God inspired them. English translations are human works that must be examined against those texts; this passage does not promise that every translation choice is without error.