20 “And He said, Where have ye laid him?” Thou knew that he was dead, and are You ignorant of the place of his burial? The meaning here is, that a man thus lost becomes, as it were, unknown to God. I have not ventured to say, Is unknown— for what is unknown to Him? But, As it were unknown. And how do we prove this? Listen to the Lord, who will yet say in the judgment, “I know you not: depart from me.” What does that mean, “I know you not”? I see you not in that light of mine— in that righteousness which I know. So here, also, as if knowing nothing of such a sinner, He said, “Where have ye laid him?” Similar in character was God's voice in Paradise after man had sinned: “Adam, where are you?” “They say unto Him, Lord, come and see.” What means this “see”? Have pity. For the Lord sees when He pities. Hence it is said to Him, “Look upon my humility [affliction] and my pain, and forgive all my sins.”
Source: Tractates on the Gospel of John (New Advent)