If you really knew me, you would know my Father as well. From now on, you do know him and have seen him.”

In a sense, the disciples have known Jesus. They spent the past couple of years living with Him, listening to Him teach, seeing Him heal the sick, talking with Him, and just spending quality time with Him. They knew Him well enough, even in the beginning of their discipleship, to leave their families, businesses, and homes to follow Him. But they still didn’t know Him in the fullness of what that means. Up till now everything has been preparation. They still do not have a full knowledge of Jesus and His significance, but things are about to change. From now on they will not only know God, but they will also “see” Him in a figurative sense (John 1:18).

John 1:18  No-one has ever seen God, but God the One and Only, who is at the Father’s side, has made him known.

Dodd has pointed out that throughout the whole Old Testament it is very rare that anyone has claimed to know God as in (Psalms 36:10). A knowledge of God is looked for as a future blessing when the Law will no longer be written on tablets of stone, but on men’s hearts. No longer will men need to admonish others to know the Lord, for they will all know Him, from the least of them to the greatest (Jer 31:31-34). Jesus sees this whole situation as completely changed. Because of what Christ did for us on the cross, an intimate knowledge of God is supposed to be the norm for the Christian today. The substitutionary death of Christ brought about the fulfillment of the prophecy in Jeremiah and we are now lving under that new covenant where we really do know God personally. “From now on, you do know him and have seen him.”

Psalms 36:10  Continue your love to those who know you, your righteousness to the upright in heart.

Jeremiah 31:31-34  “The time is coming,” declares the LORD, “when I will make a new covenant with the house of Israel and with the house of Judah.
  It will not be like the covenant I made with their forefathers when I took them by the hand to lead them out of Egypt, because they broke my covenant, though I was a husband to them,” declares the LORD.  “This is the covenant that I will make with the house of Israel after that time,” declares the LORD. “I will put my law in their minds and write it on their hearts. I will be their God, and they will be my people.  No longer will a man teach his neighbour, or a man his brother, saying, ‘Know the LORD,’ because they will all know me, from the least of them to the greatest,” declares the LORD. “For I will forgive their wickedness and will remember their sins no more.”