If we say that we have fellowship with him and walk in the darkness, we lie, and don't tell the truth.
Then in chapter 3, verse 1Jo 1:23 , "This is His commandment, that we should believe on the name of His Son Jesus Christ, and love one another as He gave us commandment." So He is our example in our relationship with each other, as we are to love one another as He gave us the commandment.