John Gill Commentary Proverbs 21:13

"Whoso stoppeth his ears at the cry of the poor, He also shall cry, but shall not be heard." — Proverbs 21:13 (ASV)

Whoever stops his ears at the cry of the poor
For want of bread; or, "of the weak", as the Septuagint and other versions; for want of help and protection, when in the greatest distress; and, with the most pressing importunity, entreats his assistance, but refuses to hear him out or relieve him, which is the same as if he had not heard him or had denied him a hearing.

He also shall cry himself; the Targum and Syriac version add, "unto God".

The sense is, that even such a one shall be brought into similar distressed circumstances, when he makes application to God and to his fellow creatures for relief and assistance: but shall not be heard; a deaf ear will be turned to him by both. The same measure he has measured shall be measured to him again; no mercy shall be shown to an unmerciful man, either by God or man; see (James 2:13) .