C. F. Keil and Franz Delitzsch on Proverbs 18:23

Pro 18:23 23 The poor uttereth suppliant entreaties;      And the rich answereth rudenesses.

The oriental proverbial poetry furnishes many parallels to this. It delights in the description of the contrast between a suppliant poor man and the proud and avaricious rich man; vid., e.g., Samachschari’s Goldene Halsbänder, No. 58. תּחנוּנים, according to its meaning, refers to the Hithpa. התחנּן, misericordiam alicujus pro se imploravit; cf. the old vulgar “barmen,” i.e., to seek to move others to Erbarmen [compassion] (רחמים). עזּות, dura, from עז (synon. קשׁה), hard, fast, of bodies, and figuratively of an unbending, hard, haughty disposition, and thence of words of such a nature (Fl.). Both nouns are accus. of the object, as Job 40:27, תחנונים with the parallel רכּות. The proverb expresses a fact of experience as a consolation to the poor to whom, if a rich man insults him, nothing unusual occurs, and as a warning to the rich that he may not permit himself to be divested of humanity by mammon. A hard wedge to a hard clod; but whoever, as the Scripture saith, grindeth the poor by hard stubborn-hearted conduct, and grindeth his bashful face (Isa 3:15), challenges unmerciful judgment against himself; for the merciful, only they shall obtain mercy, αὐτοὶ ἐλεηθήσονται (Mat 5:7).