Light and dark oppose one another like the front and back foot in walking. (English translation)
Most of the characters in this line from the Sandokai are very common Chinese words. Six out of the ten characters are part of the most basic level of Chinese proficiency for those learning it as a foreign level (HSK level 1). Only two of the characters are relatively “advanced”, one is HSK level 4 (各), and other is level 5 (暗). But in fact both of these characters are easy to recognize and have fairly simple meanings.