A fountain is a good place for a sentence that can be read in two directions. The letters do not become kinder when they turn around. They repeat the instruction.
Νίψον ἀνομήματα μὴ μόναν ὄψιν
Try it from the other end before you open the answer. The pleasure is in the mechanism, not in being told.
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It is a palindrome. Forwards or backwards, the letters spell the same sentence: wash your sins, not only your face. The line is famous from Greek fountain inscriptions. The water and the warning travel in both directions; only the penitent is asked to change.