Contradiction with Psalm 34:13
Encourages keeping one's tongue from evil, while Romans 3:13 states that the tongue is full of deceit.
Psalm 34:13: Keep thy tongue from evil, and thy lips from speaking guile.
Contradiction with James 1:26
Claims that a man who seems religious should bridle his tongue, in contrast to Romans 3:13 which suggests humanity's tongue is deceitful.
James 1:26: If any man among you seem to be religious, and bridleth not his tongue, but deceiveth his own heart, this man's religion [is] vain.
Contradiction with Proverbs 15:4
Speaks of a wholesome tongue as a tree of life, whereas Romans 3:13 describes the throat as an open sepulcher.
Proverbs 15:4: A wholesome tongue [is] a tree of life: but perverseness therein [is] a breach in the spirit. [A wholesome...: Heb. The healing of the tongue]
Paradox #1
This verse might seem to conflict with the idea of inherent goodness in people, suggesting that all have a tendency towards deceit. This can be seen as inconsistent with the belief that people are capable of choosing goodness and truth.