This was a capital punishment enjoined in the law for certain offences. Stones were thrown at the person until he was dead. In the case of Stephen he kneeled down. If the stones were aimed at the head a person would soon be stunned and fall. Paul was stoned and left for dead, but revived as the disciples stood around him. More than once the Jews took up stones to kill the Lord, but He escaped out of their hands; His death must be by being 'lifted up' from the earth. Numbers 15:35; John 10:31; Acts 7:58,59; 2 Corinthians 11:25 .