1. "When Jethro, the priest of Midian, Moses's father-in-law, heard of all that Hashem had done for Moses..." (Shemot 18:1). Rabbi Chizkiyah opened the discussion, saying: "And Aaron lifted up his hands" (Vayikra 9:22). "His hands" is spelled without Yud, thus meaning one hand only. And this is the reason, one should lift up his right hand above his left hand. And we have already explained this secret.
2. I found this in the book of King Solomon, anyone who desires to raise his hands upwards, without any prayer or request in them, will be cursed by ten potentates. These are "ten rulers who are in a city" (Kohelet 7:19). These ten potentates are designated for those who spread their hands upwards, to receive this prayer or that blessing and to bestow upon them powers through which the Holy Name is exalted and blessed from below. When the Name is blessed from below, through the spreading of the hands upwards, it then receives blessings from above. Thus, it is exalted from all sides.
3. These ten appointed potentates are there to receive the blessings from above and propel them below, to bless those who are deserving of these blessings. As it is written, "And I will bless them" (Bemidbar 6:27).
4. Consequently, man must be careful that, at the time when he raises his hands upwards, they are raised in prayer, in blessing, or in entreaty. And he must not raise his hands idly, since those ten potentates are ready and are roused towards the spreading of the hands, and if it is in vain, these ten will curse it with two hundred and forty-eight curses. This is what is written, "For he loved cursing, and it came to him" (Tehilim 109:17).
5. And thus, an impure spirit rests on these hands for its way is to rest in empty places. But blessings do not rest in empty places. Therefore, it is written, "I have raised my hand to Hashem, the most high El" (Beresheet 14:22), which is translated into Aramaic as 'with prayer.'
6. This lifting of the hands has supreme secrets. At the time that one spreads out his hands and lifts them upwards, man glorifies the Holy One, blessed be He, with many supernal secrets, and is worthy of uniting the ten sayings in order to unify the whole and bless the Holy Name properly. He also unites the inner Chariots OF ATZILUT and the outer Chariots OUTSIDE ATZILUT so that the Holy Name may be blessed from all sides, and all becomes one above and below.
7. He opened the discussion, saying, "And none shall appear before Me empty" (Shemot 23:15). This is the secret of the raising of the fingers. For when man spreads his fingers upwards, he should not do so in vain, but only with prayer, supplications and blessings. This is the secret of: "and none shall appear before Me (lit. 'My face') empty." It does not say, 'and none shall appear before Me,' but rather (lit.) "My face," which refers to the secret of the raising of the fingers - that it should not be done without an intention, as we said.
8. The ten rulers of which we spoke are the lower ten sayings, according to the secret of the inscribed letters correlating to those above; and at first, they have control of the raising of the fingers. And through this, the whole side of Holiness is united above; thus, the Other Side yields all and acknowledges the Holy King.
9. Come and behold, in the secret doctrine of Holiness, there is a king and a priest who serves under him, both above and below. The King above is the secret of the Holy of Holies, NAMELY BINAH. He is the King above; and under him there is a priest, the secret of primeval light who ministers before him, WHICH IS THE SFIRAH OF CHESED. He is the priest who is called 'great,' at the right side.
10. There is a king below, NAMELY MALCHUT, in the likeness of the King above, and he is the king over all that is below, NAMELY THE WORLDS OF BRIYAH, YETZIRAH AND ASIYAH. And under him there is a priest who ministers to him, whom we signify as Michael, the High Priest at his right hand, NAMELY CHESED. This is the true secret of Faith, the side of Holiness.