So when they continued asking him, he lifted up himself, and said unto them, He that is without sin among you, let him first cast a stone at her. He that is without sin - Αναμαρτητος, meaning the same kind of sin, adultery, fornication, etc. Kypke has largely proved that the verb ἁμαρτανειν is used in this sense by the best Greek writers.
Let him first cast a stone at her - Or, upon her, επ' αυτῃ. The Jewish method of stoning, according to the rabbins, was as follows: The culprit, half naked, the hands tied behind the back, was placed on a scaffold, ten or twelve feet high; the witnesses, who stood with her, pushed her off with great force: if she was killed by the fall there was nothing farther done; but, if she was not, one of the witnesses took up a very large stone, and dashed it upon her breast, which generally was the coup de grace, or finishing stroke. This mode of punishment seems referred to, Matthew 21:44. However, this procedure does not appear to have been always attended to. See Leviticus 24:16, and John 8:59 of this chapter.