But not everything can be done all at once...
But not everything can be done all at once, hence Islam advises a practical course to follow. It asks the individual human being to “first” locate himself in the universe by understanding his relationship with his Maker and apply his will according to this understanding in the domain where it can be applied from the outset—that is on his own self.
Hence, a personal routine of worship (which is the only appropriate action with respect to the Perfect Being who holds his very existence in His hands) is what is called for. But even worship is too much to be done all at once, and it too requires other smaller acts which prepare the worshiper and set the scene, so to speak; hence the idea of “ritual purity.” Ritual purity is an idea that is found in all religions.
It requires that the worshipper be in the right physical and mental state, so as to make the spiritual state that the particular act of worship aims for more probable. Now as the physical and mental characteristics of human beings differ according to their mental or physical health, their age, or their gender, it would not be worthy of an all-wise and all-knowing Creator to allow the state of ritual purity to be achieved by all these different types of human beings in the same way.
Hence there exist different laws of ritual purity for the different classes and states that human beings hold. Women, being the childbearing members of the human race who as a consequence of the fact undergo menstruation and postnatal bleeding, have special laws of ritual purity. These laws have been carefully derived by jurisprudents from authoritative sources and are firmly based in the written and oral tradition of orthodox Islam.
Developments in jurisprudential methods and the natural accretions that the outcome of such methods is given to, has meant that a vast and very accurate set of rules has been collected over the centuries. The vastness is such that there is felt the danger of the average woman not being able to navigate her way through the rules, or perhaps worse, of her losing sight of the forest for the trees.
To start with the second of the two, it can be said that the danger of actually getting lost in the details of the rules of ritual purity and forgetting the purpose of worship, religion, and existence itself is a very real danger.