Cross reference
1 Corinthians 2:11
11 For who among men knoweth the things of a man, save the spirit of the man, which is in him? even so the things of God none knoweth, save the Spirit of God.
Proverbs 20:27
27 The spirit of man is the lamp of Jehovah, Searching all his innermost parts.
Jeremiah 17:9
9 The heart is deceitful above all things, and it is exceedingly corrupt: who can know it?
Proverbs 14:10
10 The heart knoweth its own bitterness; And a stranger doth not intermeddle with its joy.
Romans 11:33-34
33 O the depth of the riches both of the wisdom and the knowledge of God! how unsearchable are his judgments, and his ways past tracing out!
34 For who hath known the mind of the Lord? or who hath been his counsellor?
1 Corinthians 2:10
10 But unto us God revealed `them' through the Spirit: for the Spirit searcheth all things, yea, the deep things of God.
Proverbs 20:5
5 Counsel in the heart of man is `like' deep water; But a man of understanding will draw it out.