‘But as many as received him, to them he gave the right to become children of God, even to those who believe on His name.'
But even in the world in its darkness there would be those who responded, and they would thereby receive the right to ‘become the children of God, by ‘believing on His Name'' that is, by believing in Him for what He really is. John here makes a clear distinction between general humanity, who view themselves as ‘children of God' in a general sense; the Jews, who saw themselves as God's children in a special way (Deuteronomy 14:1), and believers in Jesus who become children of God in a unique sense through being born of the Spirit (John 1:14; John 3:6). And he stresses that it is the last only who are the true children of God. For this is the purpose for which the Word has come. He has come to bring men to God and to give them the life of the Spirit, and it is only through that, and through a loving response to His word, that they can be His children. For to be the children of God means being ‘perfect, even as He is perfect' (Matthew 5:48), something which can only be found by response to Jesus, by belief and trust in Him.
‘Those that believe on His name'. The verb is followed by eis signifying ‘believe into'. This phrase is used regularly by John denoting personal, responsive faith as apart from just credence (compare John 2:24 - although the difference is not always held).