Quoting_commentary for Deuteronomy 15:13

וְכִֽי־תְשַׁלְּחֶ֥נּוּ חָפְשִׁ֖י מֵֽעִמָּ֑ךְ לֹ֥א תְשַׁלְּחֶ֖נּוּ רֵיקָֽם׃

And when thou lettest him go free from thee, thou shalt not let him go empty;