We must also clearly understand the meaning of the request "and let Your countenance shine upon Your desolate Sanctuary," as well as the reason given, "for the L-rd's sake."
The explanation is as follows: The Talmud1 states: "Daniel's prayer was not denied only because of Avraham's merit, as it is written: 'And now... for the L-rd's sake.' "
Daniel should have said "for Your sake," so why did he say "for the L-rd's sake?" The Talmud explains that he meant that his request be granted in the merit of Avraham, who also called to G-d using the term "L-rd." As Rabbi Shimon bar Yochai taught: "From the moment of creation, no one called G-d 'L-rd' until Avraham did so."
In order to understand this, we must first understand the Talmud's statement that Daniel's request was granted in Avraham's merit alone. From the Talmud's expression, we gather that Daniel was indeed worthy of having his request granted in his own merit. The Talmud's expression indicates wonder; why was Daniel dependent upon Avraham's merit?
Why indeed is the Talmud perplexed at Daniel's request that his petition be granted in the merit of Avraham? We find that when Moshe prayed to G-d that He spare the Jewish people, he too mentioned the merit of the Patriarchs, as it is written:2 "Remember Your servants, Avraham, Yitzchok and Yaakov." Why then is it a matter of wonder that Daniel was answered in the merit of Avraham?
Yet another matter must be understood: From the Talmud's statement, it seems that the expression "for the L-rd's sake" is spiritually superior to the expression "for Your sake," for were the verse to have said "for Your sake," we would not know its true intent. "For the L-rd's sake," then, is more spiritually accurate. But how can "for Your sake" be an inferior expression, when the term "Your" alludes to G-d's Essence? For example, when a person says "you" to another, he is referring to the other's essence. This too is the meaning of the words, "Blessed are You," which we recite during the Shemoneh Esreh. We bless and beseech G-d Himself to fulfill our request, that His sustenance come from the Essence of His Infinite Light.
"For the L-rd's sake," however, means in the merit of Avraham, who called the A-mighty, "L-rd." Avraham performed his great service of hospitality with mesirus nefesh, making G-d's name known to even the most common nomads, expending great effort so that even they should comprehend the concept of G-dliness, and that He is master of the world. In this manner he taught that the world is under G-d's dominion.3 We must therefore understand why the expression "for the L-rd's sake," which refers to Avraham's spiritual service, is superior to the term "for Your sake," which refers to G-d's Essence.
In summary: Daniel beseeches G-d: "and let Your countenance shine upon Your desolate Sanctuary for the L-rd's sake." Why does he say "for the L-rd's sake" and not "for Your sake?" His prayer was answered in the merit of Avraham, who was the first to call G-d "L-rd." Avraham made it known to all that G-d is Creator and L-rd of the world.