Since each day of the week is ruled by a different planet, and every planet exudes its own energy, most followers of The Craft choose to do spells on a day that is in sync with their magical intent. While this could postpone the work for a few days, the delay is always well worth the wait. Why I heard you ask? Simple my child, it's because matching your intent to the right planetary influences not only empowers the magick at hand, but to a large degree, stops the possibility of Cosmic error.
While that's certainly reason enough to cross-match intent with an appropriate day of the week, some people's thinking goes one step deeper. Because performing successful magick is a time-consuming, energy-draining process, it only makes sense to get it right the first time. And there's just no point in wasting precious time and energy if your working against stacked odds.
A love spell, for example, has little or no chance for success if preformed on a Tuesday. That's because Tuesday is ruled by the planet of Mars, the planet of war. But! If you preformed it on Friday, its chances would be way better. Why? Because Friday is ruled by Venus, the planet of love. Get it now?
For this reason, always check the Influences Chart that follows when in preparation for magick. Not only will it clear the path for success, but will save you tons of time and energy in the long run. To work in any other way is like banging your head against a brick wall.
Sunday: As this day is ruled by the Sun, it provides excellent energy for efforts involving general success, business partnerships, job promotions and professional success. The magickal work involving friendships, joy, and mental or physical health also benefit from this influence.
Monday: Monday belongs to the Moon! Its energy benefits efforts dealing with women, the family, home and hearth, the garden, and medicine. It also boosts rituals involving psychic development and prophetic dreaming.
Tuesday: The planet Mars rules Tuesday. Try It for work involving men, conflict, physical endurance and strength, list, hunting, sports and all types of competition. It's also a great tool for rituals that deal with surgical procedures and political ventures.
Wednesday: Wednesday is ruled by Mercury. Its energy is most beneficial to efforts involving writers, poets, actors, teachers and students. That's because it's influences vibrate towards inspiration, communications, the written and the spoken word, and all forms of study, learning, and teaching. It also provides time to begin efforts that deal with self-improvement or understanding.
Thursday: Jupiter governs Thursday, and influences work that involving material gain, general success, accomplishments, honors and awards, or legal issues. I energies also benefit matters of luck, gambling, and prosperity!
Friday: Friday belongs to Venus, the planet of love. Since its energies are warm, sensuous, and fulfilling, it is of great benefit to efforts involving the matter of the heart, pleasure, comfort and luxury. Use it, too, for magickal work that deals with music, the arts or aromatherapy.
Sources : "The Craft: A Witches Book of Shadows"