The 260th prohibition is that we are forbidden from allowing a non-Jew who lives in our land to give unnecessary work to a Jewish servant who has sold himself [to the non-Jew].
The source of this prohibition is G‑d's statement1 (exalted be He), "You may not [let his master] rule over him with unnecessary work in front of your eyes."
We may not think that since this servant sinned against himself and sold himself to a non-Jew, that we may let him suffer the consequences of his actions. Instead, we must watch over the non-Jew and prevent him from using the Jew for unnecessary work.
In the words of the Sifra: "The verse 'You may not [let his master] rule over him with unnecessary work in front of your eyes' means that the command2 applies only when it is 'in front of your eyes.' " This means that we are not obligated to watch in his house to see whether or not he is giving unnecessary work, but that whenever we see that he is doing so, we must prevent it.
