What does the expression “on your own head” mean?
Did you do something with the best of intentions, but, in return, you got into trouble? In such situations, you can say that a person did a good thing “на свою голову” (“na svoyu golovu”) or “on his own head”.
This expression came into the Russian language from the Old Testament texts. True, in ancient times, it meant retribution for sins and crimes. For example, the Book of Daniel says: “You have lied on your head; for behold, the Angel of God, having taken a decision from God, will cut you in two.”
In modern Russian, the expression “on your own head” is also used when someone wants to warn that a person will do something to his own detriment and therefore trouble is likely.
An English equivalent would be: “Hoist with one’s own petard.”
