Faith that overcome the world

1 John 5:4-13
For everyone born of God overcomes the world. This is the victory that has overcome the world, even our faith. Who is it that overcomes the world? Only the one who believes that Jesus is the Son of God.
For there are three that testify: the Spirit, the water and the blood; and the three are in agreement.
Whoever has the Son has life; whoever does not have the Son of God does not have life.
I write these things to you who believe in the name of the Son of God so that you may know that you have eternal life.
Faith is what 'overcomes the world'.
God himself stands witness that Jesus is his Son. 'To believe is life, to disbelieve is death'.
John is writing to those who do believe, that they may know for certain that eternal life is theirs.
Why?
We can not see the God, but through Jesus Christ we believe Him and be sons of God, so we are overcome the world, because our faith overcome the world.
Faith is knew the blessing from the Lord and the promise in eternal life. Faith is shown in the life not only in the word.
How?
I believe that Jesus is son of God, so I have the eternal life and I know that the blessing of the Lord is with me.