“Hu,” the aspirant, breathy sound made at the end of the word Allah, is a sound that is hidden as a divine Name within each recitation of Allah. The relationship that Allah and Hu have with each other describes the nature of ecstasy. It does so by conveying that there is a secret within the secret. The subtle way the sound “Hu” arises at the end of the invocation “Allah” also suggests an infinite process of essence of essence of essence…

– physicians of the heart, p. 190