Greek proverb: χεὶρ την χεῖρα

Here's a saying from Apostolius, C1.36, with a Latin version from Clavis Homerica. The image is from Wikipedia. Here are some more Apostolius proverbs.

Ἁ δὲ χεὶρ την χεῖρα νίζει.
Manus manum lavat.
One hand washes the other.