For the one whom God has sent speaks the words of God, for God gives the Spirit without limit. The Father loves the Son and has placed everything in his hands. Whoever believes in the Son has eternal life, but whoever rejects the Son will not see life, for God’s wrath remains on them. John 3: 34-36
We can believe what Jesus says, because on Jesus, God poured out the spirit in full measure keeping nothing back. Even the Jews themselves said that the Prophet’s received from God a certain measure of the spirit. The full measure of the Spirit was reserved for God’s own chosen one. Now, in Hebrew thought, the Spirit of God has two functions – first, the Spirit revealed God’s truths to men; and, second, the Spirit enabled men to recognise and understand that truth when it came to them. So to say that the spirit was on Jesus in the completest possible way is to say that he perfectly knows and perfectly understand the truth of God. To put that in another way – to listen to Jesus is to listen to the very voice of God.
Finally, John again sets before men the eternal choice. That choice is life or death. All through history this choice has been set before Israel. Deuteronomy records the words of Moses .: “see I have set before thee this day life and good, death and evil… I call heaven and earth to record this day against you, that I have set before you life and death, blessing and cursing; therefore choose life, that’s both thou and thy seed may live” (Deuteronomy 30: 15-20). This challenge was reiterated by Joshua: “ choose ye this day whom you will serve” (Joshua 24: 15).
It has been said that all life concentrates upon a man at the crossroads. Once again John returns to his favourite thought. What matters is a man’s reaction to Christ. If that reaction be love and longing, that man will know life. If it be indifference or hostility, that man will know death. God offered him love; by his rejection of it he has condemned himself. It is not that God sent his wrath upon him, it is that he has brought that wrath upon himself.
William Barclay, Study Bible John Volume 1