Kabbalah к Йеошуа 1:8

The Torah teaches every person how to walk a straight path. It gives advice how to repent and return to one's Master to cancel the decree against him. Because even though a decree has been given not to cancel the decree against him, it shall nevertheless be canceled and not be applied to him anymore in this world. So for this purpose, man should occupy himself in the study of the Torah day and night, not deviate from it. As it is written, "you shall meditate therein day and night" (Joshua 1:8). So if he deviates from the Torah - or he abandons it - it is as though he abandons the Tree of Life.

Come and see how twisted we are, human beings, that we do not want to follow the ways of life that the Holy One of Blessing has taught us, God's children, the God warned us and said "and meditate upon this day and night" (Joshua 1:8) - we don't have the permission to split day from night. And so too with Yehudah, even though he separated himself and worked in the West which is [called] Night, the rest of the travels of his tents were turned to the East, which is [called] Day. And the Holy One of Blessing indicated it to him, and said "and you shall choose life" (Deut. 30:19), meaning, he should not split day from night, and a person who does so brings about death.

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."