John Gill Commentary Proverbs 1:18

"And these lay wait for their own blood; They lurk privily for their own lives." — Proverbs 1:18 (ASV)

And they lie in wait for their [own] blood While they lie in wait for the blood of others, they lie in wait for their own; and when they shed the blood of innocent persons, it eventually comes upon their own heads, and is the cause of their own blood being shed; vengeance pursues them, and justice will not allow them to live;

they lurk secretly for their [own] lives : while they are lurking in secret places to take away the lives of others, they are laying snares for their own souls; and the consequence will be, that they will be brought to a shameful and untimely end here, or, however, to everlasting ruin and destruction hereafter.