לֹא־תָח֥וֹס עֵֽינְךָ֖ עָלָ֑יו וּבִֽעַרְתָּ֧ דַֽם־הַנָּקִ֛י מִיִּשְׂרָאֵ֖ל וְט֥וֹב לָֽךְ׃ (ס)
Thine eye shall not pity him, but thou shalt put away the blood of the innocent from Israel, that it may go well with thee.
Read kabbalistic (mystical) interpretation of Deuteronomy 19:13: and classical mystical sources.