Matthew Henry's Complete Bible Commentary
Verse 13
A malicious mischievous man is here represented, 1. As ungrateful to his friends. He oftentimes is so absurd and insensible of kindnesses done him that he renders evil for good. David met with those that were his adversaries for his love, Psalms 109:4. To render evil for evil is brutish, but to render evil for good is devilish. He is an ill-natured man who, because he is resolved not to return a kindness, will revenge it. 2. As therein unkind to his family, for he entails a curse upon it. This is a crime so heinous that it shall be punished, not only in his person, but in his posterity, for whom he thus treasures up wrath. The sword shall not depart from David’s house because he rewarded Uriah with evil for his good services. The Jews stoned Christ for his good works; therefore is his blood upon them and upon their children. MHBCC 646.13