Ascents and descents are a sign of life. The changing of the seasons, the periodicity of the changes in human nature, the reincarnations, the global crises, the economic upsurges and declines are all an inseparable part of life.
It is impossible to advance in a constant current, since we have to develop constantly. Life is a development and this development is possible only thanks to the contractions and the expansions. This is called the secret of life.
This is actually what is happening to us now. The Creator takes our ego and doesn’t leave us anything. As a result there is a contraction, an exhalation. Thus He gives us now a chance to expand by ourselves. Then He contracts us again and we have to expand once more.
By these actions of contractions and expansions the process of “breathing” takes place—this is the pulse of life.
From the 3rd part of the Daily Kabbalah Lesson 9/24/12, The Study of the Ten Sefirot