Stay your/somebody's hand - Idioms by The Free Dictionary
stay your/somebody's hand
stay (one's) hand
To stop or prevent someone or oneself from doing something. The board was prepared to fire him over the offense, but they stayed their hand and opted to suspend him from his role instead. See if you can stay her hand before she signs the deal.
stay your/somebody’s ˈhand (old-fashioned or literary) stop yourself/somebody from doing something; prevent somebody from doing something: He reached for his keys, but Rosa stayed his hand.