What do you mean both sides of the road are in the air? Where does this sentence come from?

1, the two sides of the avenue are in the sky, which means: from now on, you and I will not interfere with each other, you will live your life, I will live my life, and we will no longer contact each other, which is related to the complete end.

This sentence comes from the early days of the liberation war. When Mao Zedong retreated from Yan 'an, he said, "The road leads to the sky, and each person is half way. You go your way and I'll go mine. " This is one of the most wonderful expositions about maintaining the "freedom" of war.