Koan
Not the wind not the flag
Two monks argued over a flag. One said the flag was moving. The other said the wind was moving. Huineng said, "Not the wind, not the flag. Mind is moving."
The Gateless Gate, case 29
How to sit with it
The next time something irritates you, look for what is actually moving.
Read it once more, slowly. Then sit for two minutes and let it stay in the background. There is nothing to solve. New to this? Read what a koan is.