We have the words that John wrote to believers years after the resurrection to affirm this belief: "We declare to you what was from the beginning, what we have heard, what we have seen with our eyes, what we have looked at and touched with our hands, concerning the word of life....." 1 John 1:1
John is affirming this belief in order to convince others who had strayed from the truth. The purpose was so that they would be included in the fellowship with John and his followers. This outreach was so that "our joy may be complete." Have we thought about connecting joy with outreach? If we can reach others with the truth of Christ, joy ought to follow.
Also, what I see in this passage from our First Reading (1 John 1:1 - 2:2) is the importance of fellowship. Especially after the resurrection, this fellowship would be strategic.
Blessings to you as you gather for worship on Sunday.