Luke: In the law (principally the book of Leviticus) there are a number of prohibitions regarding blood which may lead to personal uncleanness. It was not unusual for the priests to “expand” on certain prohibitions in order to safeguard against violating the commands. Though I suppose the priest and this Levite avoided the victim, because they were of Levitical or priestly descent, they would certainly have been very sensitive of becoming unclean. That is not the point. The Samaritan may not have had such scruples but rather moved by empathy attended the man come what may.