John 14:29

Jesus’ reason for saying what He did was not to cause the disciples embarrassment but to strengthen their faith. Their faith would grow stronger after the Resurrection and Ascension (cf. John 13:19). The disciples would then view Jesus’ teaching here as fulfilled prophecy.

John stressed the importance of believing throughout his Gospel (cf. John 1:50; John 3:12; John 3:15; John 4:21; John 4:41; John 5:24; John 5:44; John 5:46; John 6:29; John 6:35; John 6:47; John 6:64; John 7:38; John 8:24; John 8:45; John 9:35; John 10:38; John 11:25; John 11:41; John 12:37; John 12:44; John 13:19; John 14:1; John 14:11; John 16:31; John 17:20; John 20:27). Jesus’ statement here returns to that theme. Both Jesus and John wanted to build faith in disciples of Jesus.