For the next little while we are going to be looking at the book of 1 John. This book is the first in a series of three epistles (letters) written by the apostle John. It is actually the second book in the New Testament written by him; the first is simply called 'John' and is an account of Jesus' life. 1 John can be found after 2 Peter and comprises of 5 chapters. So let's dive in...
We proclaim to you the one who existed from the beginning, whom we have heard and seen. We saw him with our own eyes and touched him with our own hands. He is the Word of life. 2 This one who is life itself was revealed to us, and we have seen him. And now we testify and proclaim to you that he is the one who is eternal life. He was with the Father, and then he was revealed to us. 3 We proclaim to you what we ourselves have actually seen and heard so that you may have fellowship with us. And our fellowship is with the Father and with his Son, Jesus Christ. 4 We are writing these things so that you may fully share our joy. (1 John 1:1-3, NLT)
In these verses, John is letting us know that Jesus (who all the apostles were raving about) didn't just come into existence when He was born as a man through the Virgin Mary. No, Jesus is the Word of life. He was there with the Father in the beginning when the world was created and everything was made through Him (John 1:1-3). Jesus always existed, but when He took on human form, He gave mankind a chance to tangibly experience God (see, hear and touch); to tangibly experience life.
The 12 apostles had the chance to exprerience life with Jesus whilst He was physically on the earth. When Jesus rose from the dead, He also appeared to them and this is what they wanted us to know. The same truth that gave them so much joy is still true today and has been passed on from generation to generation. They wanted us to know that the same way they had fellowship (friendly association) with Jesus whilst He was on the earth, we who believe and put our faith in Him can also join in this fellowship.