Proverbs 26:4-5

Do not answer [nor pretend to agree with the frivolous comments of] a [closed-minded] fool according to his folly, Otherwise you, even you, will be like him. Answer [and correct the erroneous concepts of] a fool according to his folly, Otherwise he will be wise in his own eyes [if he thinks you agree with him]. [Matt 16:1-4; 21:24-27]