Sorcery is a field of study that calls upon the magic of the planet. Rather than using their own natural energies which are finite, an individual uses the energy of nature and the world around them. This form of magic is unlimited and never runs out. The user doesn't control the magic directly as it is too massive and powerful, but rather guides it in a particular way as it flows through them. A person opens themselves up to the flow of magic through rituals. This requires a combination of chanting, movement, and runes specific to the spell or culture of the participants.
These rituals can also require hours to months of preparation, as well as various materials and a period of ritual cleansing or fasting. Magic resulting from these rituals are not permanent, and last as long as the spell is being performed. An example would be a rain dance, or a spell altering a landscape for a particular amount of time. These rituals always take a particular form. Weaker spells can be performed by a group of up to eight witches. For stronger spells, more participants are needed and both genders are used. One warlock is needed for every group of eight witches that are added to the circle.
Why would rituals need to be set up in this way to work?