Contradiction with Genesis 11:7
This verse speaks about God confounding language at Babel, resulting in people not understanding one another, which contradicts the call for clarity in communication in 1 Corinthians 14:9.
Genesis 11:7: Go to, let us go down, and there confound their language, that they may not understand one another's speech.
Contradiction with Matthew 13:13
This verse talks about Christ speaking in parables so that those who hear do not understand, which contrasts with the emphasis on speaking clearly understood words in 1 Corinthians 14:9.
Matthew 13:13: Therefore speak I to them in parables: because they seeing see not; and hearing they hear not, neither do they understand.
Contradiction with Isaiah 6:9-10
These verses imply a divine intention for people to hear but not understand, which is opposite to the intention expressed in 1 Corinthians 14:9.
Isaiah 6:9-10: And he said, Go, and tell this people, Hear ye indeed, but understand not; and see ye indeed, but perceive not. [indeed, but understand: or, without ceasing, etc: Heb. in hearing, etc]
Contradiction with Ezekiel 3:6
Here, God tells Ezekiel he is being sent to a people who understand his speech, unlike the notion of unclear speech in 1 Corinthians 14:9.
Ezekiel 3:6: Not to many people of a strange speech and of an hard language, whose words thou canst not understand. Surely, had I sent thee to them, they would have hearkened unto thee. [of a...: Heb. deep of lip, and heavy of language] [Surely...: or, If I had sent thee, etc. would they not have hearkened unto thee?]
Contradiction with Mark 4:34
This states that Jesus explained everything to His disciples privately, which could contrast with the general instruction of clear communication to all in 1 Corinthians 14:9.
Mark 4:34: But without a parable spake he not unto them: and when they were alone, he expounded all things to his disciples.
Contradiction with John 16:25
Jesus speaks of using parables and proverbs, speaking openly only at a later time, which could oppose the encouragement of clear understanding in 1 Corinthians 14:9.
John 16:25: These things have I spoken unto you in proverbs: but the time cometh, when I shall no more speak unto you in proverbs, but I shall shew you plainly of the Father. [proverbs: or, parables]
Contradiction with 2 Corinthians 12:4
This verse mentions unspeakable words not lawful for a man to utter, which could contradict the directive for comprehensible speech found in 1 Corinthians 14:9.
2 Corinthians 12:4: How that he was caught up into paradise, and heard unspeakable words, which it is not lawful for a man to utter. [lawful: or, possible]