Because things are the way they are, things will not stay the way they are.

In German: "Weil die Dinge sind, wie sie sind, werden die Dinge nicht so bleiben wie sie sind." - As quoted in Dictionary of Contemporary Quotations (1976) by John Gordon Burke and Ned Kehde, p. 224, also in The Book of Positive Quotations (2007) by John Cook, p. 390