There is no religion in the world where there is a possibility of spiritual development outside of the context of that religion. This is only a modern invention. For example, Christian mystics were also Christians. They also went to Church and followed Christian laws. Hindu mystics were practicing Hindus; they didn't kill cows and have steak. They follow the Hindu laws and so on and so forth down the line and Sufism is no exception.

The love of God is not only the highest form of love, but also in reality the only love of which all other loves are but shadows

If you want to make a decision in life on what to do, but if you're trying systematically, through spiritual practice, through meditation, through the invocation of the name of God, to walk closer and closer in this life to Him, you need someone to guide you. And God has made it possible in Islam for this guidance to exist.

Sufism has always had the function of purifying Islamic ethics and that fasting and tazkiya is like lighting a lamp.

Without Sufism, Islam would not have spread into two thirds of what we call the Islamic world.

Sufis have always been those that have tried to purify the ethics of Islam and society. And they don't have their hands cut off from the external action at all. For example, the bazaar in which the Sufis were very strong always dominated economic life in Islamic world. They could give a much more sane and Islamic form of activity when the economic life of Islam moved out of the bazaar to new parts of Islamic cities with modernized Muslims, who took it in another light and it became very, very anti Islamic, and much against many of the most profound practices of Islamic societies.

The significance of the vast Islamic scientific tradition for Muslims and especially for young Muslims today is not only that it gives them a sense of pride in their own civilization because of the prestige that science fhas in the present day world. It is furthermore a testament to the way Islam was able to cultivate various sciences extensively without becoming alienated from the Islamic world view and without creating a science whose application would destroy the world of nature and the harmony that must exist between man and the natural environment.