Kabbalah su Salmi 145:15

These eyes illuminated by Torah, of which it is written (Psalms 145:15) "The eyes of all look to you expectantly, and you give them food when it is due." Man must, therefore, to delve into them regularly: morning, evening and afternoon, always, the Holy One looking into Her eyes - as it is written (Deuteronomy 11:12) "The eyes of the Lord your God are always looking at her (the land of Israel), from the beginning of the year until its end." And we connect the words [in the two verses], the daily sacrifice (tamid) and "the eyes of the Lord God always (tamid) looking at her". And the (Tamid) sacrifice was [offered] in the morning and the evening, like the recitation of the Shema prayer. From this we learn that one who recites the Shema in the evening and the morning, it is as if one has fulfilled the commandment of continually studying Torah, day and night, as it is written (Joshua 1:8) "Let not this Book of Torah cease from your lips, but recite it day and night."