Negative commandment · Lo Ta’aseh #299 of 613
Not to mislead an unsuspecting person
שלא להכשיל תם בדרך
The verse · Vayikra 19:14
לֹא־תְקַלֵּל חֵרֵשׁ וְלִפְנֵי עִוֵּר לֹא תִתֵּן מִכְשֹׁל וְיָרֵאתָ מֵּאֱלֹהֶיךָ אֲנִי ה׳
“Thou shalt not curse the deaf, nor put a stumbling block before the blind, but shalt fear thy God: I am the Lord.”
The Rambam’s words
Not to mislead an unsuspecting person, as [Leviticus 19:14] states: "Do not place a stumbling block before the blind."
שלא להכשיל תם בדרך, שנאמר "וְלִפְנֵי עִוֵּר לֹא תִתֵּן מִכְשׁוֹל" (ויקרא יט, יד).
Why · Sefer HaChinuch #232
To not make an innocent one stumble on the way
“The root of the commandment is well-known, since the guidance of people and to give them good advice for all of their actions [is needed for] the ordering of the world and its civilization.”
Who & when
“And it is practiced in every place and at all times by males and females.”
Where in the Mishneh Torah
Hilchot Murderer and the Preservation of Life הלכות רוצח ושמירת נפש