"For you will not abandon my soul to Sheol; you will not allow your pious one to see the Pit." (Psalms 16:10) The Holy One, blessed be He, is called the "pious one" as it says, "For I am pious," says the Lord (Jeremiah 3:12). David also called himself a "pious one" as it says, "Guard my soul, for I am pious" (Psalms 86:2). Rabbi Alexandri said: Anyone who hears his disgrace and remains silent is called a pious one. David heard his disgrace and remained silent, therefore he is called a pious one.
"Teach me the way of life." Rabbi Yudan said, "David said before the Holy One, blessed be He, 'Teach me the way of life.' And He said to him, 'You desire life? Look to the fear of the Lord, for fear of the Lord adds days.' Rabbi Azariah said, 'David said before the Holy One, blessed be He, "Teach me the way of life." And He said to him, "You desire life? Look to the Torah, for it is a tree of life to those who hold fast to it."' Rava said, 'David said before the Holy One, blessed be He, "Teach me the way of life." And He said to him, "You desire life? Do good and eat well, for pleasantness is in your right hand, and victory."' Two Amoraim said different explanations: one said it refers to those who come to study Torah, as it says, 'From His right hand came a fiery law for them' (Deuteronomy 33:2); and the other said it refers to scribes and teachers of children, who are destined to dwell in the shadow of the Holy One, blessed be He, as it says, 'I have set the Lord always before me.' Another interpretation is 'Teach me the way of life.' Rabbi Avin said it refers to the proper reading of the Torah on Rosh Hashanah and Yom Kippur, and the seven species of the Land of Israel. 'Satiated with joy from Your countenance' - do not read 'satiated', but rather 'satiated sevenfold.' These are the seven classes of righteous individuals who will see the face of the Divine Presence in the World to Come, as it says, 'You will make me know the way of life; the fullness of joys is in Your presence.' Do not read 'fullness', but rather 'sevenfold.' And it also says, 'And those who love Him are like the sun when it goes forth in its might.'"