The answer is in the mathematics of Kabbalah: 2 + 7 = 9: The Hermit of the Tarot, Yesod, the sacred forces of the Solar Logos, the Holy Spirit within our body, and the path of initiation that leads out of suffering. 9 is the number of solar generation, since through Yesod all things come into being. Therefore, the 27th is the most solar Christic day of the month, since it embodies the heightened activity of Solar Christic forces animating our macrocosmic and microcosmic universe.

To elaborate, it is good for us to perform the Rune Laf every morning of the 27th of each month. The position is quite revealing: we place our hands, palm up, near our genitalia, in order to receive the solar effluvia within our hands and sexual organs, which is where the solar forces accumulate within our organism. We do so in order to empower our body, mind and soul, as well as to fulfill any petition or prayer. Prayer is empowered through this Rune, specifically since it is the 27th and works with the sexual force.