
Everything that is, is true but some truths are beyond our human reasoning.
So in the fulness of time God's reveled himself through the human nature of his Son. Christ referred to himself with the enigmatic expression "Son of Man" which in general refers to His integral relationship with all mankind. This phrase recalls that He was descended from the House of David, that He was born of the Virgin Mary, that He suffered and died as man under the Roman governor, Pontius Pilate. In other words, Christ was a true human being in history. On the other hand "Son of Man" was also used by Christ to point to his divinitiy. When he was asked by the high priest whether he was the "Son of God", he answered that he was the "Son of Man" who would be coming in power and great glory. (Mt 26:63)
Christ claimed to be the Son of God by nature as He said, "The Father and I are one." (Jn 10:30) Did He speak the truth? In another passage we read, "And if I should say that I do not know him, [the Father] I would be like you a liar." (Jn 10:15) So Christ claimed to speak the truth which is correspondence between what He knew to be true and his verbal expression of it. To show that he was speaking the truth he performed many signs or miracles; He healed the sick by a simple touch or a word, raised the dead and by saying, "Be still" He calmed the storm on the Sea of Galilee.
What purpose would he have to lie? His declaration before the High Priest to be the Son of God brought Jesus the death sentence. As he stood before Pilate He declared that He had come into the world to testify to the truth and that anyone who belonged to the truth would listen to his voice. "Pilate said to him, 'What is truth?'" (Jn 18:38)
Christ did not only speak the truth but declared--

What does this mean?
"Truth as a person means that the universe does not function in a mechanical way, controlled by impersonal laws. Yes, there are laws which govern the phenomena, seen and unseen. But these laws are expression of the will and power of a Person who is the Truth, who holds the universe together." Webpages: Angel Manuel Rodriguez: "Truth in Person") To accept Christ into our lives as the Son of God means that "You will know the truth, and the truth will set you free". (Jn 8:32) Christ frees us from sin and the narrowness of self-sufficiency. He lead us into the unending life with God. He is the Way, the Truth and the Life.