Summary: We have the prophetic word fully confirmed in Jesus.
THE FOUNDATIONAL AUTHORITY OF SCRIPTURE
The church is built upon the foundation of the apostles and prophets, Jesus Christ Himself being the chief corner stone (Ephesians 2:20). At the back of Peter’s apostolic testimony to the transfiguration of our Lord (2 Peter 1:16-18) lies the foundational authority of the Old Testament Scriptures (2 Peter 1:19-21). Later on he will make the bold move of adding Paul’s writings to his list of canonical books (2 Peter 3:15-16).
When Jesus was reproving the Sadducees with their unbelief (Matthew 22:31-32), He did not ask whether they had heard that which was spoken to Moses, but whether they had heard “that which was spoken to you”. Neither did He ask whether they had heard that which was spoken to them by Moses, but whether they had heard “that which was spoken to you by God”. The Bible is the Word of God direct to you!
“And we have more sure the prophetic word” (2 Peter 1:19) refers back to the Old Testament. Peter is reassured of the truth of the old prophecies by what he has witnessed in the mount of transfiguration, and so looks forward all the more to what it anticipates. Confronted with those who are offloading their own doubts on the young believers, he is claiming for his own experience the same authority as Scripture.
You would do well to be “taking heed” to the prophetic word, as to a lamp shining in the midst of the obscure darkness of this dungeon of a world. What a gloomy prospect we have if we ignore the Word of God! But into this murky world comes a “light shining” - exactly the words which Jesus used of the last of the Old Testament style prophets, John the Baptist (John 5:35).
And there is the anticipation that a day will dawn, the very day that the new teachers deny, a day of judgement (Malachi 4:5) and of salvation (Acts 3:19-21). The nearness of that day should effect our style of life (Romans 13:11-14), our desire to have fellowship with like-minded people (Hebrews 10:25), and our witness to the unbelieving world (1 Peter 2:12).
Balaam was a prophet who was hired to curse Israel, but could only speak the true words of God (2 Peter 2:15-16). He foresaw the day of judgement as the rising of a “star” in Israel (Numbers 24:17). John the Baptist’s father saw the first coming of Christ as an early visitation of the “dayspring” (Luke 1:78-79).
The “morning star” is actually the planet Venus, the first to reflect the sun’s rays in the morning. Peter speaks of a similar refreshing dawn “within our hearts”. Jesus identifies Himself as the “bright and morning star” (Revelation 22:16).
When Jesus returns, believers will enter into a new level of experience (1 John 3:2). We will be “face to face” with God (1 Corinthians 13:12). “Until” then, we can be sure of the truth of the old prophecies: Jesus is coming back!
What we must understand above all, says Peter, is that “no prophecy of Scripture is of its own interpretation” (2 Peter 1:20). The voice of God taught the three disciples the significance of the transfiguration (2 Peter 1:17): similarly the prophets were given some understanding of the things which they saw (e.g. Jeremiah 1:11-14). The visions were from God, and the words by which they convey those visions to us are also inspired by God.