Igbo proverb

Aka ekpe kwọọ aka nri, aka nri akwọ aka ekpe.

Help is strongest when it goes both ways.

Literal translation: The left hand washes the right, and the right washes the left.
Explanation: Each hand can wash the other more easily than itself. The image speaks of mutual help.
When to use it: When two people or groups can support one another.