The eternal Word of God became incarnate in this world as Jesus of Nazareth. The apostles saw, heard, touched, witnessed and declared Him to the world, including the people John writes to. Some dishonest and hypocritical teachers unsettled their faith. He writes so that they will know that they know Him, applying two objective tests in these verses. The first is obedience to God’s commandments, and the second is a specific application, love for the brethren.