عَلَيَّ أَلْفٌ
I owe one thousand.
This acknowledgement appears to impose liability for a thousand, but it does not by itself specify the underlying transaction or the kind of currency. An addition such as “from the price of this slave” links the obligation to a particular sale; “in the currency of a certain town” identifies the monetary standard.
One must interpret the entire connected statement, not detach the opening words from later qualifications. Where subsequent wording specifies the basis or medium of payment, that clarification guides the legal analysis.