. [If] someone says to a worker, ‘‘Here is an issar for you, pick vegetables for me today,’’ his earnings are permissible. [But if one said,] ‘‘Pick vegetables for me today in return for it,‘‘ his earnings are prohibited. [If] one took a loaf worth a pundyon from a baker [and said], ‘‘When I pick field vegetables I will bring you [some],’’ it is permissible. But if he took from him as usual, he may not pay him with seventh [-year] money, for one may not repay a debt with seventh [-year] money.