That which we have seen and heard declare we unto you, that ye also may have fellowship with us: and truly our fellowship is with the Father, and with his Son Jesus Christ. 1 John 1:3.
John was known as one of the sons of thunder. For three years he walked with Jesus, personally. He knew what it was like to eat with Him, to travel with Him, to touch Him, to help Him with His necessities. And for three years John bickered and argued with the other disciples about who was going to be the greatest. For three years he still remained a son of thunder. For those who think that conversion and walking in fellowship with Jesus always changes one overnight, and if it doesn't happen, one doesn't have a genuine experience, consider James and John and the other disciples.
They fought and argued right up to the end of their time with Jesus--in the upper room they were still bickering about who was going to be the greatest. They didn't "slip" into arguing! They spent hours walking along the road, debating the subject. And they were so aware of what they were doing that they lagged behind Jesus, and He would end up in town a quarter of a mile ahead of them!
And when they finally caught up to Him, He would ask, "What were you talking about?"
And they would change the subject. They were embarrassed to admit what they had been doing, but they didn't stop doing it.
Jesus treated them kindly, tenderly, and John continued to walk with Jesus even after Jesus left. Years later he wrote it down, "Truly our fellowship is with the Father, and with his Son Jesus Christ." He was speaking in the present tense.
As John had continued his walk with Jesus, continued to commune with Him day by day, he had been transformed. Now, instead of asking "Who's the greatest?" and seeking the highest place, he said, "Beloved, let us love one another, for love is of God."
The purpose of the devotional life is to come into fellowship with Jesus. The purpose of walking, talking, and communion with Him is for fellowship. And ultimately, through this fellowship, we will become like Him.