Romans 2:15; Romans 8:16; Romans 9:1

15 Which shew the work of the law written in their hearts, their conscience also bearing witness , and their thoughts the mean while accusing or else excusing one another ;)
16 The Spirit itself beareth witness with our spirit, that we are the children of God:
1 I say the truth in Christ, I lie not, my conscience also bearing me witness in the Holy Ghost,