And furthermore: it is a precept (mitzvah) to be occupied in Torah – day and night. It is this that is written: (Josh. 1:8)... and you shall meditate upon it day and night... And can a person be occupied in Torah, all day and night for all his days? And yet: ‘The blessed Holy One does not come to overburden His creations!’cxxiiiBT’Avodah Zarah 3a But anyone who recites the Shm’a every day, morning and evening, it is as if he had thereby fulfilled:... and you shall meditate upon it day and night.cxxivSee BT Menaḥot 99b