Chapter 29
Laws Derived from Isaiah: Running, Walking, Commerce, Measuring, Reading, Speaking
BUYING AND SELLING ON BHABBATH AND YOM TOV
22. One may ask the shopkeeper for a particular number of articles, as is common, for example, in the case of bottles so long as one’s intention is to let him know how many one needs (and not to enable him to work out the cost)
23.a. A person who takes merchandise from a shopkeeper on Shabbath, in the ways mentioned above, and still owes him money for purchases made before Shabbath should not specify the new cumulative balance on Shabbath.
23.b. The cumulative balance may be stated neither in weight, in measure, in money nor in number.
23.c. For instance, it is prohibited to tell the shopkeeper
1) that one now owes him such-and-such a sum including the previous debt, or
2) that one now owes him altogether for goods aggregating in weight, measure or number to whatever the total is of the new and previous transactions.
