Sifrei Mitzvot sur Le Deutéronome 24:10

He prohibited us from taking collateral from borrowers into our hands except by the order of the judge and through his messenger; and that we not come, ourselves, into the debtor's house and take it as collateral. And that is His saying, "you must not enter his house to seize his pledge" (Deuteronomy 24:10). And the language of the Mishnah (Bava Metzia 113a) is, "One who lends money to another may take collateral only by means of the court. And he may not enter his house to take his collateral, as it is stated, 'You shall stand outside' (Deuteronomy 24:11)." And it is a negative commandment that is rectified by a positive commandment. And that is His saying, "You must surely return the pledge to him" (Deuteronomy 24:13). And so is it explained at the end of Tractate Makkot (Makkot 16a). And know that if he does not return it and does not fulfill the positive commandment in it, he is liable for lashes, and pays the money of the collateral - as it is explained at the end of Makkot. And the regulations of this commandment have already been explained in the ninth [chapter] of [Bava] Metzia. (See Parashat Ki Teitzeh; Mishneh Torah, Creditor and Debtor 3.)