‘For God loved the world so much that he gave his only begotten Son, that whoever believes on him should not perish but have everlasting life'.
The message is now expanded. The reason that Jesus has come is because “God loved the world so much that He gave His only Son”. This is the amazing new revelation that surpasses all that has gone before, that God was such that He had not only seen man's need but has met it in the only way possible at greatest cost to Himself. ‘In this is love, not that we loved God but that He loved us, and gave His Son to be a propitiation for ours sins' (1 John 4:10).
A further interesting fact is that it is ‘the world' that is in view. His love is reaching out to the world. Jesus is not just a Messiah for the Jews, He is the Christ for the world, the world that is in darkness (John 1:10). He has come to be a light to every man.
The point is that there was no other way by which salvation and deliverance could come to mankind, only by God's giving of His only Son to die on the cross, ‘wounded for our transgressions, bruised for our iniquities --- the Lord laid upon him the iniquity of us all (Isaiah 53:5-6. See Luke 22:37 for Jesus' own application of this chapter to Himself). This is the full meaning of the title ‘the Lamb of God' (John 1:29; John 1:36).
Here Jesus' distinctiveness is again being drawn out. ‘His only Son', ‘the only Son from the Father' (John 1:14; John 1:18), Who was in the bosom of the Father (in closest personal relationship) and Who made the Father known and revealed His glory (John 1:18), is the One Who will be offered up for sin.
And the purpose? Negatively, to save men from ‘perishing'. Positively, that they might have eternal life. In Plato's Immortality to ‘perish' meant to be destroyed utterly. He used it as the opposite of being an immortal soul. As Paul says, God alone has immortality (1 Timothy 6:16). We will no doubt read into this what we will.