What Sin Does to Sinners (vv. 9-11). Our enemies think they are hurting us, but they are really hurting themselves. The trouble they cause us will only come right back on their own heads, for it is an inexorable law of God that people reap what they sow. They dropped burning coals on David’s head, but God would return the same to them (see 11:6; 18:8; 120:4; Prov. 25:22; Gen. 19:24). The destructive fires they lit with their tongues would burn them, and they would fall into the pits they had dug for David (v. 10; see 7:15; 9:15; 35:7-8; Prov. 26:27). They hunted David and set traps for him, but evil would eventually hunt them down and destroy them (v. 11). “Be sure your sin will find you out” (Num. 32:23).