DID JESUS BEAR WITNESS TO THE TRUTH, OR HAS IT ALWAYS BEEN EVIDENT?

John 18:37  Pilate therefore said unto him, Art thou a king then? Jesus answered, Thou sayest that I am a king. To this end was I born, and for this cause came I into the world, that I should bear witness unto the truth. Every one that is of the truth heareth my voice. (KJV) Romans 1:18-20  For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness;  Because that which may be known of God is manifest in them; for God hath shewed it unto them. For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse: (KJV)

One who is arguing for this being a contradiction needs to read the Romans passage more closely.  It acknowledges that many people deny the existence of God, despite the fact that God has, through their very creation, showed them that He exists.  So, while the truth has always been evident, many people still don't believe it.  That is why Jesus (and his followers) bear witness to the truth, to help persuade those who deny God.  Not a contradiction.