John 8:55
Yet ye have not known him; but I know him: and if I should say, I know him not, I shall be a liar like unto you: but I know him, and keep his saying. Yet ye have not known him; but I know him: and if I should say, I know him not, I shall be a liar like unto you: but I know him, and keep his saying.
This verse belongs to Jesus' teaching as the Light of Life recorded in John 8:12-59 and continued in John 9. It was spoken in the court of the temple in connection with the services of the Feast of Tabernacles. After the evening sacrifice two lofty standards supporting great lamp-stands were kindled to commemorate the pillar of light that guided Israel in the desert and to point to the coming of the Messiah. In the morning when the sun had risen above the Mount of Olives and lit the marble palaces and the gold of the temple walls, Jesus declared Himself the source of spiritual light who illumines the darkness of the world.
Those Jesus addressed claimed to know God but did not know Him. Their refusal to love and receive Jesus, whom God sent, showed that they had turned away from God. By contrast Jesus truly knows God the Father and keeps His word, His knowledge being shown in keeping the Father's saying. For Jesus to deny that He knew God would have made Him a liar like His hearers.
In the surrounding exchange, Abraham's obedient faith at the command to offer his son opened before him the coming of Christ. By faith Abraham saw Christ as the incarnate Saviour and Lamb who would die for humanity's sins, and rejoiced.