When and where Jesus spoke these words are not specified. John seems to be giving a general summary of Jesus’ manifestation of Himself to the nation.
The fact that Jesus “cried out” seems to mean the importance of the issues before the nation. Jesus is the perfect manifestation of God. God is the one who sent Him. John 1:18; http://ref.ly/Co1.15 and http://ref.ly/He1.3. To believe in Jesus is to believe in God. There are no two objects of faith: God and/or Jesus. When one sees Jesus, he sees the Father who sent Him. John 12:41; 14:9. Jesus came to lead people out of Satan’s kingdom of darkness into God’s kingdom of love and light. John 1:4, 9; 8:12; 12:35; Col. 1:13-14.
Jesus is God’s Word (Logos) to people, God spoke decisively and finally in Him. Note http://ref.ly/He1.1-3. The issue is the command of the Father. To obey the Father is to come to eternal life–see John 12:50. To reject God’s word which is Jesus’ very word (v. 48; cf. v50b; 7:16; 14:10, 24. This is to abide in death. Moses spoke of the coming of the great Prophet. He would speak for God. Moses told Israel that they must listen to Him. Deut. 18:15. Condemnation at the last day is the penalty for rejecting the One whom the Father sent (Deut. 18:18-19; John 3:18, 36; 5:24.
The purpose of God’s revelation in Jesus is positive: He came to save–not judge. John 12:47–see John 3:17. Note John 9:39. Rejection of God’s revelation inevitably brings a hardening in sin and ultimately God’s judgment.
John approached Jewish national unbelief by balancing his theological explanation with Jesus’ serious exhortation to the nation to repent. In the words of Moses, these “are not just idle words for you–they are your life” http://ref.ly/Dt32.47