The Request - John 12:20-22
The reputation of Lazarus rising from the dead was putting on pressure and the Jews were divided. The Jewish authorities were actively seeking to kill Jesus (John 11:43- 57). It was even getting dangerous for Lazarus (John 12:1-19 cp. Matthew 21:1-46). Meanwhile, Gentile proselytes were asking to see Jesus. Prior to His triumphal entry into Jerusalem at the time of the Passover, Jesus was secluding Himself (John 11:53-56). So, this group of Gentiles were probably expecting a private interview with Jesus.
The Answer - John 12:23-26
Jesus did not give them an interview. He gave them a word-picture / an image for their minds: a corn / grain of wheat. It must go into the ground and die in order to bring forth a harvest. The hour had come for Christ's death and resurrection. He was not someone to keep around forever to do miracles and favors for men. Jesus must invest Himself in the greatest work of all: purchasing our redemption and guaranteeing our resurrection unto eternal life (Mark 10:45).
Jesus was not interested in people merely "seeing" Him (i.e. pursuing an intellectual understanding). To truly see Him, a person would have to follow Him, serve Him, and die to self. The goal is not to know about Jesus and satisfy curiosity, but to begin a relationship, making a life-changing choice, and enter into the satisfaction of the Father ("…him will my Father honor" - John 12:26). See also John 5:19-24; I John 2:2, 22-23; 4:9-10 cp. Matthew 7:21-23.
The Struggle - John 12:27-30
When Jesus said that His soul was troubled, He was indicating a great burden - a great struggle within Himself, as He considered the effect of our sins being laid upon Him and receiving the wrath of God for those sins (II Corinthians 5:21; Isaiah 53:4-6; Galatians 3:13; I Peter 2:21-25; Luke 22:42-44 cp. Hebrews 12:2-4).
The Division - John 12:31-36
Christ's death and resurrection will attract people and bring them to the Father. Eternal life and membership into God's Family and Kingdom are given to us through Jesus Christ only (John 6:27-40; 14:1-6, 15-26). At the same time Christ will bring division into this world. Those who believe Him not, but follow this world and Satan, the god of this world, shall be judged and separated from God and His people forever. The test is whether you will walk in the light or stay in the dark (Matthew 10:32-40; John 3:16-21; 6:35-36; 8:12, 23-36; 12:37-50 cp. II Corinthians 4:3-6; Ephesians 5:1-17).