1 John 1:1-4 That which was from the beginning, which we have heard, which we have seen with our eyes, which we looked upon and have touched with our hands, concerning the word of life— (2) the life was made manifest, and we have seen it, and testify to it and proclaim to you the eternal life, which was with the Father and was made manifest to us— (3) that which we have seen and heard we proclaim also to you, so that you too may have fellowship with us; and indeed our fellowship is with the Father and with his Son Jesus Christ. (4) And we are writing these things so that our joy may be complete.
In this introduction to his letter, John refers to two groups of people. "You" referring to the recipients of the letter (and by extension those of us reading) and "We" probably referring to himself and the other apostles. They are the ones who have seen the manifestation of that which was from the beginning. They have touched the word of life and testify to it.
The main call in this introductory statement is to join them in fellowship as they are already joined in fellowship with the Father and his Son, Jesus Christ (v.4). They proclaim a message. Not a new message because it has been there from the beginning(v.1). Not a message which has no basis in reality because they have looked upon it with their eyes and touched it with their hands(v.1). A message about the word of life, that became flesh and through whom we can obtain eternal life(v.1-2). And as we listen to them and believe in the one they proclaim, we join with them in fellowship as they are in fellowship with God - Father, Son and Spirit(v.3-4). This will make their joy complete.
In a world where we are always eager for the next new thing and trends change everyday; it is reassuring to be reminded that our gospel is an old, unchanging message that has been there from the beginning.
In a world of subjective truth and fake news; it is encouraging to know that the gospel we have is real and centered on a real historical figure and proclaimed by witnesses who testify to its truthfulness.
In a world where people believe that there are multiple ways to fellowship with God; it is important to know that the only way we can have fellowship with God is by holding on to the Word of Life - Jesus the Christ - as proclaimed by the Apostles.