Contradiction with Proverbs 29:11
While 1 Samuel 21:14 describes David behaving like a madman, Proverbs 29:11 emphasizes the wisdom in restraining one's spirit, contrasting David's apparent loss of control.
Proverbs 29:11: A fool uttereth all his mind: but a wise [man] keepeth it in till afterwards.
Contradiction with 2 Timothy 1:7
1 Samuel 21:14 shows David feigning madness; however, 2 Timothy 1:7 speaks of God giving a spirit of power, love, and a sound mind, implying a contradiction in behavior.
2 Timothy 1:7: For God hath not given us the spirit of fear; but of power, and of love, and of a sound mind.
Contradiction with 1 Corinthians 14:33
David's behavior in 1 Samuel 21:14 appears chaotic, whereas 1 Corinthians 14:33 states that God is not the author of confusion, presenting a contradiction.
1 Corinthians 14:33: For God is not [the author] of confusion, but of peace, as in all churches of the saints. [confusion: Gr. tumult, or, unquietness]