(1) The foundation of piety and the root of perfect service [of G-d] is for a man to clarify and come to realize as truth what is his obligation in his world and to what he needs to direct his gaze and his aspiration in all that he toils all the days of his life.
(2) Behold, what our sages, of blessed memory, have taught us is that man was created solely to delight in G-d and to derive pleasure in the radiance of the Shechina (divine presence). For this is the true delight and the greatest pleasure that can possibly exist. The place of this pleasure is, in truth, in Olam Haba (the World to Come). For it was created expressly for this purpose.
(3) But the path to arrive at the "desired haven" (Ps. 107:30) of ours is this world. This is what our sages of blessed memory said: "this world is like a corridor before the World to Come" (Avot 4:16).