John 16:29-30 His disciples said to Him, "See, now You are speaking plainly, and using no figure of speech! Now we are sure that You know all things, and have no need that anyone should question You. By this we believe that You came forth from God."
This was his last few words with His disciples. Our Lord told them that soon (after His crucifixion, resurrection and the coming of the Spirit of truth) His words and parables would become plain and simple to them. His disciples immediately proclaimed that they understood Him clearly, and that He was sent by God and that with His great knowledge and wisdom He would be able to rule Israel. righteously. They missed out completely that His coming was as the sacrificial Lamb for the propitiation of sins.
Gen 6:5 Then the Lord saw that the wickedness of man was great in the earth, and that every intent of the thoughts of his heart was only evil continually. And the Lord was sorry that He had made man on the earth, and He was grieved in His heart.
Since the fall of Adam, God regretted making man, for the intent and thoughts of his heart is continually evil. This also applies to the disciples of Jesus. Since the appearance of John the Baptist on the scene to prepare the path for the coming of the Messiah, many Jews repented and believed in the soon coming of the Messiah. So when our Lord Jesus appeared, performing many signs and wonders, healings, etc. and teachings with great knowledge and wisdom, many Jews believed Him as the coming Messiah.
Mat 16:15,20-21 Simon Peter answered and said, "You are the Christ, the Son of the living God."... Then He commanded His disciples that they should tell no one that He was Jesus the Christ. From that time Jesus began to show to His disciples that He must go to Jerusalem, and suffer many things from the elders and chief priests and scribes, and be killed, and be raised the third day.
His disciples gave up everything to follow Him when He called them for they were looking forward to serve the King of Israel their Messiah or Christ. They were looking forward to be His officials, filled with riches, honours, power, respect and glory.
They purposely ignored His departure or death.
"Again, I leave the world and go to the Father"
Only a few minutes earlier our Lord reminder them again of His coming death (going back to Him) in John 16:5 "But now I go away to Him who sent Me, and none of you asks Me, 'Where are You going?" They refused to accept His death for they would not followed the sacrificial Lamb, led to be slaughtered.
Brethren, are we not like the disciples of Jesus - choosing to believe and accept only blessings that are beneficial to us in this world? Just like His disciples, we too have witnessed all types of signs and wonders, healings, etc. with the gifts of the Holy Spirit in Jesus name. Just like His transformed disciples at Pentecost, we too need the Helper, the Spirit of truth, to teach and guide us into all truth so that we are set free from worldliness and are transformed to set our minds on the things above. Just like His disciples in the book of Acts, we too empowered with the Holy Spirit can minister in truth, power, love and signs.
Brethren, since you have purified your souls in obeying the truth through the Spirit in sincere love of the brethren, love one another fervently with a pure heart, having been born again, not of corruptible seed but incorruptible, through the word of God which lives and abides forever. (1Pet 1:22-23)