John 14:7 "If you had known Me, you would have known My Father also; and from now on you know Him and have seen Him."
Jesus' disciples witnessed His numerous miracles. Healing the sick, blind, crippled and deaf, casting out demons, walking on water, raising the death, etc. To Him nothing was impossible. They also believed that He was the coming Messiah to deliver Israel.
Mat 16:14 So they said, "Some say John the Baptist, some Elijah, and others Jeremiah or one of the prophets."
Because of their concept that Yahweh, the Almighty God is righteous, holy but judgmental, and that no sinful human having seen God can stay alive, they could only believe Him as another prophet like Elijah or Moses. So when our Lord taught them things difficult to accept they abandoned Him. (John 6:66 From that time many of His disciples went back and walked with Him no more)
John 6:67-69 Then Jesus said to the twelve, "Do you also want to go away?" But Simon Peter answered Him, "Lord, to whom shall we go? You have the words of eternal life. Also we have come to believe and know that You are the Christ, the Son of the living God."
But the twelve disciples, who followed Him and had been living together with Him in His new found family, confessed Him as 'the Son of the living God' which was revealed by God to them.
Mat 16:15-17 He said to them, "But who do you say that I am?" Simon Peter answered and said, "You are the Christ, the Son of the living God." Jesus answered and said to him, "Blessed are you, Simon Bar-Jonah, for flesh and blood has not revealed this to you, but My Father who is in heaven."
Brethren, to get revelations from God (just like His 12 disciples) we need to spend as much time as possible before His presence in our quiet time - reading His word and reflecting on His love, longsuffering, care, and deliverance of His sinful and rebellious people (Jews) in the OT and His warnings of heresies and the rebellious and depraved Christians in these last days, so that we are involved with Him (in prayers by confiding in Him our gratitude, concerns, feelings, understanding, etc. of His pains and difficulties caring for us) in His work of perfecting us, in the fulfillment of His will and the advancement of His kingdom.