Dig your own grave
Definition 1 of 1
Pro Tip 1/3Negative Outcome
Used when an action will likely lead to a bad result, often by one's own doing. 
Ignoring her warnings, you're really digging your own grave.
Pro Tip 2/3Self-Inflicted Trouble
It emphasizes trouble that you bring onto yourself, not caused by others. 
By betraying his team's trust, he was digging his own grave.
Pro Tip 3/3Idiomatic Caution
Used to advise someone against a course of action that seems harmful. 
If you cheat on the test, you're digging your own grave.