Contradiction with Proverbs 18:2
Proverbs 18:2 suggests that a fool has no interest in understanding, which contradicts Proverbs 26:6 as sending a message by the hand of a fool implies expecting some level of responsibility and cognizance from them.
Proverbs 18:2: A fool hath no delight in understanding, but that his heart may discover itself.
Contradiction with Proverbs 14:7
Proverbs 14:7 advises to stay away from a foolish man, contradicting Proverbs 26:6 where a message is entrusted to a fool.
Proverbs 14:7: Go from the presence of a foolish man, when thou perceivest not [in him] the lips of knowledge.
Contradiction with Proverbs 19:1
Proverbs 19:1 states that a poor person with integrity is better than a fool with perverse lips, contradicting the notion of entrusting anything valuable or important to a fool as suggested implicitly in Proverbs 26:6.
Proverbs 19:1: Better [is] the poor that walketh in his integrity, than [he that is] perverse in his lips, and is a fool.
Contradiction with Proverbs 26:4
Proverbs 26:4 advises not to answer a fool's folly, contradicting the idea of Proverb 26:6 where a fool is relied upon to carry out a task.
Proverbs 26:4: Answer not a fool according to his folly, lest thou also be like unto him.
Contradiction with Ecclesiastes 7:5
Ecclesiastes 7:5 suggests that it is wise to listen to rebuke from the wise rather than amusement from fools, contradicting the trust placed in a fool as implied in Proverbs 26:6.
Ecclesiastes 7:5: [It is] better to hear the rebuke of the wise, than for a man to hear the song of fools.
Paradox #1
The contradiction in Proverbs 26:6 could be seen as advising against sending messages through foolish people, yet it can be inconsistent because everyone makes mistakes or acts foolishly at times. It suggests avoiding the imperfect human condition, which is not always practical or fair.