17. At all times, uninterruptedly, the teaching of life pours down upon the earth. It is impossible to imagine earthly existence without this connection with the Unseen World. Like a lifeline, like a guiding light, the Teaching consolidates our progress in the midst of darkness. But in the midst of the showers of blessing, as with the waves of the sea, one can perceive a rhythm with a particularly decisive increase when the teachings appear. In this way, the rhythm of the whole world can be explained by waxing and waning, in a word, the evolution of existence can be recorded.