2. "Dyeing" means "being polluted", which means bad social atmosphere. "Sober" means sober. This refers to distinguishing right from wrong. Generally speaking, people should maintain their kind nature, and at the same time distinguish right from wrong in society.
There are other sentences with similar meaning to the original text: there was nothing, where did the dust come from? This sentence comes from the four famous sentences of Huineng, the sixth ancestor of Zen Buddhism in China.