What is truth?
St. Isaac answers thus:
“Truth is the perception of things that is given by God.”
In other words: the perception of God is truth.
If this perception exists in a man, he both has and knows the truth. If he does not have this perception, then truth does not exist for him.
Such a man may always be seeking truth, but he will never find it until he comes to the perception of God, in which lie both the perception and knowledge of truth.
St Justin Popovich