1 Corinthians 2:11
For who among men knoweth the things of a man, but the spirit of a man which is in him? so also the things of God no one knoweth, but the Spirit of God.
Romans 2:15
and shew the work of the law written on their hearts, their conscience witnessing together with it, and their own thoughts either accusing, or excusing them,)
2 Corinthians 4:2-6
but have rejected shameful disguises, not walking in craftiness, nor handling the word of God deceitfully; but by the manifestation of the truth, recommending ourselves to every man's conscience, in the sight of God.
Hebrews 4:12-13
For the word of God is lively and efficacious, and sharper than any two-edged sword, piercing even to the dividing of soul and spirit, and of the very joints and marrow, and judging the thoughts and intentions of the heart.
1 John 3:19-21
And hereby we know that we are of the truth, and shall assure our hearts before Him.