Contradiction with Proverbs 12:22
This verse states that lying lips are an abomination to the Lord, while 1 Samuel 15:16 involves the Lord sending a message through Samuel about Saul's disobedience, which could be seen as contradictory if considering the act of communication through deception.
Proverbs 12:22: Lying lips [are] abomination to the LORD: but they that deal truly [are] his delight.
Contradiction with Numbers 23:19
This verse asserts that God is not man, that He should lie, nor the son of man, that He should repent. This contradicts 1 Samuel 15:16 if one interprets God as changing His mind about Saul.
Numbers 23:19: God [is] not a man, that he should lie; neither the son of man, that he should repent: hath he said, and shall he not do [it]? or hath he spoken, and shall he not make it good?
Contradiction with James 1:17
This verse emphasizes that God does not change or cast shifting shadows, which can be seen as contradictory to the situation in 1 Samuel 15:16 where God's regret concerning Saul's kingship is addressed.
James 1:17: Every good gift and every perfect gift is from above, and cometh down from the Father of lights, with whom is no variableness, neither shadow of turning.
Contradiction with Malachi 3:6
This verse declares that the Lord does not change, which appears to contrast with the idea of God expressing regret or changing His mind about Saul's kingship in 1 Samuel 15:16.
Malachi 3:6: For I [am] the LORD, I change not; therefore ye sons of Jacob are not consumed.