414. Rabbi Yosi opened the discussion saying, "Serve Hashem with fear, and rejoice with trembling" (Tehilim 2:10). It is also written, "Serve Hashem with gladness, come before His presence with singing" (Tehilim 100:2). Come and see, only a man who serves the Holy One, blessed be He, should worship Him morning and evening.
415. When light appears in the morning, there is an awakening of the right side, CHESED, in the world. It behooves man then to cling to the right of the Holy One, blessed be He, and worship Him through prayer, for prayer brings power and strength from above, and draws blessings from the supernal deep, BINAH, to all the SUPERNAL worlds, whence blessings flow upon the lower beings. Thus, upper and lower are blessed through the service of prayer.
416. The service prayer should be performed before the Holy One, blessed be He, with gladness and singing, CHESED AND GVURAH, in order to include the Congregation of Yisrael, THE NUKVA, between them, and to properly bring about union TO ZEIR ANPIN, as it is written, "Know that Hashem He is Elohim" (Tehilim 100:3). This is the secret of union in the secret of the service.
417. Nevertheless, man should worship the Holy One, blessed be He, with gladness and show joy in his service. Corresponding to the two, gladness and singing, are the two prayers and two daily offerings; of the two, gladness is in the morning and singing in the evening. Therefore, "The one lamb shall you offer in the morning, and the other lamb shall you offer at evening" (Bemidbar 28:4).
418. The evening service is therefore optional, since at that time She distributes prey among the legions. It is no time to be blessed but to deal sustenance. In the daytime, She is blessed by the two sides, CHESED AND GVURAH, in morning and evening with gladness and singing. At night, She gives the blessings to those who deserve it. Hence it says, "She rises also while it is yet night, and gives food to her household..." (Mishlei 31:15).