C. F. Keil and Franz Delitzsch on Proverbs 18:13

Pro 18:13 13 If one giveth an answer before he heareth,      It is to him as folly and shame.

The part. stands here differently from what it does at Pro 13:18, where it is subj., and at Pro 17:14, where it is pred. of a simple sentence; it is also here, along with what appertains to it in accordance with the Semitic idiom, subj. to 13b (one who answers ... is one to whom this...); but, in accordance with our idiom, it becomes a hypothetical antecedent. For “to answer” one also uses השׁיב without addition; but the original full expression is השׁיב דּבר, reddere verbum, referre dictum (cf. ענה דּבר, Jer 44:20, absol. in the cogn., Pro 15:28); דבר one may not understand of the word to which, but of the word with which, the reply is made. היא לו comprehends the meaning: it avails to him (ducitur ei), as well as it reaches to him (est ei). In Agricola’s Fünfhundert Sprüchen this proverb is given thus: Wer antwortet ehe er höret, der zaiget an sein torhait und wirdt ze schanden [he who answers before he hears shows his folly, and it is to him a shame]. But that would require the word to be יבושׁ, pudefiet; (היא לו) כּלמּה means that it becomes to him a ground of merited disgrace. “כּלמּה, properly wounding, i.e., shame (like atteinte à son honneur), from כּלם (cogn. הלם), to strike, hit, wound” (Fl.). Sirach Sirach(11:8) warns against such rash talking, as well as against the rudeness of interrupting others.