Lifnei iver (Hebrew: לפני עיוור), meaning "before the blind", is a phrase used to describes the sin of placing a stumbling block before a blind person.
The origin of this phrase comes from the Book of Leviticus 19:14-
" לֹא-תְקַלֵּל חֵרֵשׁ--וְלִפְנֵי עִוֵּר, לֹא תִתֵּן מִכְשֹׁל; וְיָרֵאתָ מֵּאֱלֹהֶיךָ, אֲנִי יְהוָה."
"Thou shalt not curse the deaf, nor put