Contradiction with Proverbs 17:27
While Acts 26:1 shows Paul readily defending himself, Proverbs 17:27 suggests restraint and sparing use of words is a sign of knowledge and understanding.
Proverbs 17:27: He that hath knowledge spareth his words: [and] a man of understanding is of an excellent spirit. [an...: or, a cool]
Contradiction with Matthew 5:39
Acts 26:1 demonstrates self-defense and explanation, whereas Matthew 5:39 advises turning the other cheek instead of defending oneself.
Matthew 5:39: But I say unto you, That ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also.
Contradiction with James 1:19
Acts 26:1 depicts Paul speaking promptly in his defense, yet James 1:19 emphasizes being slow to speak and quick to listen.
James 1:19: Wherefore, my beloved brethren, let every man be swift to hear, slow to speak, slow to wrath:
Contradiction with Ecclesiastes 3:7
Acts 26:1 involves Paul defending himself before Agrippa, while Ecclesiastes 3:7 speaks to there being a time to be silent, and a time to speak, suggesting perhaps restraint in some contexts.
Ecclesiastes 3:7: A time to rend, and a time to sew; a time to keep silence, and a time to speak;