Rumi, the Sufi teacher of Persia, says, "O sleep, in thee I find the divine bliss. Thou makest patients forget their illness; thou makest kings forget for the moment that they are in a palace; thou makest the prisoners forget for a moment that they are in captivity. What bliss, what joy of bliss when the soul is freed from these limitations, from the presence of the different aspects of life that are keeping it captive!'