Musar zu Tehillim 145:15

The camp of Ephrayim, which faces West, the direction of our prayers, the direction of the שכינה, the Holy of Holies, is the region behind which the angel רפאל is positioned We find an allusion to this in Moses' prayer for Miriam, 12,13, "א-ל נא, רפא נא לה" Prayer corresponds to the letter ו in the Ineffable Name of G–d, because the conditions for successful prayer are 3, i.e. in reality 6. 1) Prayer is called עין ולב, eye and heart. It is called "eye," because Psalms 145,15, says: "all eyes are on You." It is called "heart," since the Torah in Deut 11,13, requires us to serve the Lord "with all your hearts." This demand may appear as a contradiction in terms.