King James Version
But thou shalt surely kill him; thine hand shall be first upon him to put him to death, and afterwards the hand of all the people.English Standard Version
But you shall kill him. Your hand shall be first against him to put him to death, and afterward the hand of all the people.New International Version
You must certainly put him to death. Your hand must be the first in putting him to death, and then the hands of all the people.