Spiritual Practices-Purim-Kav haYashar-Raising Hands
The 15th of Adar is the Yahrtzeit of Rav Zvi Hirsch Kaidanover, the Kav haYashar: It is very precious to God that you raise your hands with spread fingers when you are praying from the depth of your heart. Also when you wash your hands before prayers, and before eating, say the blessing over the washing as you dry them, and raise them up to receive the holiness.
The Torah tells us about Abraham, who said, “I have raised my hands to God the Most High (Genesis 14:22).” The Targum says, “I have lifted my hands in prayer.”
About Moses it is written how when he prayed for the defeat of Amalek, “and when Moses raised his hands, Israel would be victorious in the battle (Exodus 17:11).”
And so, when you are praying or making blessings or saying praises of God, it is even obligatory to lift up your hands and fingers. (Kav haYashar, Chapter 63)