Passage
And we write these things to you, that our joy may be fulfilled.
And we write these things to you, that our joy may be fulfilled.
1 John 1:2 (and the life was revealed, and we have seen, and testify, and declare to you the life, the eternal life, which was with the Father, and was revealed to us);
1 John 1:3 that which we have seen and heard we declare to you, that you also may have fellowship with us. Yes, and our fellowship is with the Father, and with his Son, Jesus Christ.
1 John 1:4 And we write these things to you, that our joy may be fulfilled.
1 John 1:5 This is the message which we have heard from him and announce to you, that God is light, and in him is no darkness at all.
1 John 1:6 If we say that we have fellowship with him and walk in the darkness, we lie, and don’t tell the truth.
The verse centers on "write", "things", and "fulfilled". It is saying that the verse draws attention to "write" and "things", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 3's "that which we have seen and heard..." into verse 5's "This is the message which we have...", so "write" and "things" belong inside that flow. In 1 John context, the local focus is Christ, faith, and discipleship.
A plain takeaway is to answer the verse's own emphasis on "write" and "things" with trust shaped by these words, not by a vague optimism outside the passage.