‘These things have I written to you, that you may know that you have eternal life, even to you who believe on the name of the Son of God.'
And these things are written to his hearers and readers so that they might know that they have eternal life (John 5:24), because they believe on the name of the Son of God. This faith in Him and all He has done for them, has produced eternal life now within them. They are born from above (John 3:6; James 1:18; 1 Peter 1:23; 2 Peter 1:4). They are children of God (1 John 3:1-2; John 1:12-13). They have eternal life. And it comes through belief in what He essentially is (His name) as God's Son.