(John 16:12-13)….. “I still have many things to say to you, but you cannot bear them now. 13 “However, when He, the Spirit of truth, has come, He will guide you into all truth; for He will not speak on His own authority, but whatever He hears He will speak; and He will tell you things to come. “Into all truth” in verse thirteen is translated “into the full truth” or “to the complete truth” in other Bible translations. At the very end of His earthly ministry, Jesus told His disciples there were many things He still needed to teach them, but at the moment they were not ready to recieve the teaching. Jesus told them that when the Holy Spirit would come, He would lead them into the truth of what Jesus had been teaching them.
Only after His death and resurrection, which brought in the New Covenant, was the Lord able, through the Holy Spirit, to explain all He had accomplished for them (us) at the cross of Calvary. Again, it is the Holy Spirits role to lead us into all truth, but it is impossible to be led into all truth only through the four Gospels: Matthew, Mark, Luke, and John. This is not to say the four Gospels are not truth, for they are. They are very important for they reveal Jesus to us. But they do not, and cannot, give us the complete and full picture of truth. For Jesus plainly said the Holy Spirit would guide His disciples into all truth only after Jesus left them, and the four Gospels primarily cover the earthly ministry of Jesus. So it is only in the Letters (also called Epistles) to the Church (Romans through Revelation) that we finally get the complete picture of the New Covenant and understand what Jesus has accomplished. All the more reason to study those vital books of the Bible. Jesus did not give us the full, complete truth during His earthly ministry. Without the revelation of what Jesus accomplished through His death and resurrection, we don’t have the whole picture. This information was only given to us after Jesus’ resurrection, and is found only in the Letters written to the Church. The Letters to the Church in the New Testament are also the words of Jesus, speaking to us from Heaven through the Holy Spirit, and written down by His apostles. It is right for us to honor the words of Jesus recorded in the four Gospels, but it is a mistake to think we should place them on a higher level than the revelation Jesus gave His church after His resurrection. What we have in the Epistles are not just the words of men, but the Words of God, written down by the Apostles of Jesus. This is where we must look to be led “into all truth” which Jesus promised His disciples would be revealed after He left them and sent the Holy Spirit. If you are going to understand truth fully, you need divine illumination through all of the word of God. So happy studying, start digging, get ready to be brought into all truth.