“they set an ambush for their own souls.” It is a consistent theme through Scripture that evil people bring evil upon themselves. This can happen in many different ways, and often in multiple ways at the same time. Sometimes the righteous people in a society catch the evildoers and judge and punish them. Sometimes, because evil people associate with other evil people, they get betrayed by the people they were working or dealing with. Also, consistently evil people often become attacked by demons who afflict them physically, mentally, and spiritually. Also, always, evil people are eventually judged by God and get the righteous consequences of their evil actions.
Evil may seem to pay off in the short term, but eventually, it results in terrible consequences. Many verses say that the evil deeds of evil people will eventually come upon their own heads (cp. 1 Kings 8:32; Ps. 7:15-16; 9:15; 10:2; 35:8; 57:6; 94:23; 140:9; 141:10; Prov. 1:31; 5:22; 11:5; 14:14; 26:27; 28:10; Jer. 2:19; Ezek. 11:21). [For information about evil and ungodly behavior opening a person up to demonic attacks, see commentary on Prov. 13:21].