Hebrew · Sifrei Devarim (Hebrew)
למען אשר לא ילמדו אתכם לעשות. מלמד שאם עושים תשובה, אין נהרגים.
English · Shraga Silverstein
(Devarim 20:18) "So that they not teach you to do according to all their abominations": whereby we are taught if they repented, they are not killed.