"We have also a more sure word of prophecy; whereunto ye do well that ye take heed, as unto a light that shineth in a dark place, until the day dawn, and the day star arise in your hearts." (2 Peter 1:19)
In this important passage, Peter explains the ultimate source of his writings. He did not merely repeat cunningly devised fables when he taught majestic things about the Lord Jesus Christ, but was himself an "eyewitness" of His glory and personally heard the very voice of God on the Mount of Transfiguration (v. 16-18). The three chosen disciples witnessed His prophesied glory and heard God speak of Christ's pleasing Sonship. There could be no doubt of God's special plan for His Son. As eyewitnesses, they bore the onus of bearing witness to the facts.
But he downplayed the importance of his own personal testimony, even though it was a firsthand account and quite important, and he knew it was absolutely correct. The "more sure word of prophecy" he recommended, however, which outshines any human testimony, was the written Word of God, for the Transfiguration confirmed numerous Old Testament prophecies concerning Christ. Prophecies already fulfilled multiply our confidence in the rest of Scripture.
Oral or written testimony of human observers, no matter how trustworthy they may be, is still subject to human error, and not "inerrant" in the same way as Scripture. Christians must always remember that the written Word of God is more certain than personal memories or impressions. The experiences we have must never be viewed as validating God's Word. Rather, God's Word validates our experiences. The early church only had a few portions of the New Testament in those days of beginning, but thankfully, we have it all, and have ready access to it. Peter recognized it as superior to any personal testimony. How much more should we deem it trustworthy and authoritative? JDM