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.

Instead, you must surely kill him. Your hand must be the first against him to put him to death, and then the hands of all the people.

The hands of the witnesses shall be first upon him to put him to death, and afterward the hands of all the people. So thou shalt put the evil away from among you.

The hands of the witnesses shall be the first in putting him to death, and after that, the hands of all the people. So you must purge the evil from among you.