Contradiction with Proverbs 15:13
This verse states that a merry heart makes a cheerful countenance, which contrasts with the notion in Job 15:12 of one's heart leading to deceitful thoughts.
Proverbs 15:13: A merry heart maketh a cheerful countenance: but by sorrow of the heart the spirit is broken.
Contradiction with Job 17:11
This verse expresses a heart filled with brokenness and lost purposes, contrasting with the idea in Job 15:12 of responding with self-deception.
Job 17:11: My days are past, my purposes are broken off, [even] the thoughts of my heart. [the thoughts: Heb. the possessions]
Contradiction with Psalm 33:21
This verse describes a heart rejoicing in the Lord, which contradicts Job 15:12's suggestion of a heart causing straying or deceitful pondering.
Psalm 33:21: For our heart shall rejoice in him, because we have trusted in his holy name.