I bought a number of items from a store and realized when I got home that they forgot to charge me for one item. Is it considered stealing if I don't go back and pay for it?
The Aish Rabbi Replies:
Being that the item did not come into your possession as a result of outright stealing, it technically does not fall under the commandment of "Do not steal."
However, in many cases, this would fall under another Torah prohibition against "cheating" (onah). As derived from Leviticus 25:14, we are obligated to pay for an item if we were inadvertently undercharged, or not charged at all. (Code of Jewish Law - C.M. 227:1)
There is another reason to return to the store and pay. It is a great opportunity to fulfill the mitzvah of "Kiddush Hashem" -- sanctifying God's Name. The last time I was undercharged at a store, I went back to pay the difference, and the store manager made such a big deal about my honesty, that it was a bit embarrassing. That should be the worst embarrassment we suffer!