The 244th prohibition is that we are forbidden from stealing money.
The source of this prohibition is G‑d's statement,1 "Do not steal."
In the words of the Mechilta, "The verse 'Do not steal' constitutes the prohibition of financial theft."2
One who transgresses this prohibition must pay back according to the formula written in the Torah — either two, four, or five times the amount stolen, or only the actual value.3
The Sifra says, "The verse4 that says 'He must pay back double' [the value of the stolen object] teaches us the penalty. What teaches us that the act is prohibited?5 The verse 'Do not steal' — even if just to disturb." This phrase ["just to disturb"] means when the intention is to [not really steal, but only to temporarily] anger and confuse the victim, and afterwards return it to him. The Sifra continues,] "the verse, 'Do not steal,' teaches that you may not do so, even if you intend to pay him back four or five times the value."
The details of this mitzvah are explained in the 7th chapter of tractate Bava Kama.