A question I am often asked is, "What is a Sufi?" Sufis are Muslims who emphasize essence over form and substance over appearance in their spiritual practices.
If the institution of religion can be compared to a cup and the water in it is the spiritual message, Sufis lament that we spend too much time polishing the outside of the cup and neglect to drink the water.
They do subscribe to outer rituals, but are mostly eager to do the inner work. They aspire to taste and live the essence of their faith. To give an example of the Sufi approach to teachings, a conservative Islamic theologian might say that a Muslim who does not perform the five cycles of daily prayers will suffer punishment in the hereafter. A Sufi teacher, on the other hand, will liken prayers to attendance at celestial banquets. A practitioner who fails to pray is missing out on the joy of the feast. That loss is the punishment.