Interestingly, the witch's pentacle is also associated with the number eight:
The pentagram is actually the geometric design depicting how the planet Venus moves in the heavens, and it is from this design that they believe the people of the Euphrates-Tigris region drew the first pentagram 8000 years ago. The pentacle is reflective of Venus' pattern in the sky from our point of view and the circular motion of Venus around the sun.
If we chart Venus synodic orbital time in the zodiac, we find she moves through 5 positions as the Morning Star, which takes exactly 8 years plus 1 day  - and forms the design of the pentacle in the vault of the heavens. [2, quote]
In Jewish kabbalah, the planet Venus planet corresponds with both the power to actualize potential and the archetype of Moshe Rabbeinu, the first and the final redeemer.
Taking all these ideas together, we can see within the pentacle symbolism the mystical dynamic - from 8 (assiyah) to 8000 (atzilut) - of brit milah, transformation, messianic consciousness and geulah.
 suggests a day of "im hakolel" surrounding the 8 years
 Solitary Witch, Silver RavenWolf (p. 309)