keine schlafenden hunde wecken

listen to the pronunciation of keine schlafenden hunde wecken
German - English
let sleeping dogs lie
To leave things as they are; especially, to avoid restarting or rekindling an old argument; to leave disagreements in the past

Eventually, they decided it would be best to let sleeping dogs lie and not discuss the matter any further.

(Atasözü) Do not make (someone) angry and cause trouble or danger; do not make trouble if you do not have to. "Don't tell Father that you broke the window. Let sleeping dogs lie."
don't stir up trouble