Give (one) enough rope to hang (one)self phrase
To allow someone to continue doing something wrong or harmful to themselves and then suffer the consequences of such a way of acting.
I knew he cheated on his wife but gave him enough rope to hang himself.
A: Should I tell the teacher that Mary is cheating? B: No. Give her enough rope to hang herself.
When the police stopped asking me and let me keep talking, I felt like they were giving me enough rope to hang myself.
The verb "give" must be conjugated according to its tense.
This phrase dates back to the mid 17th century.