The speech shifts from backbiting to addressing them in a manner of turning, which is more effective in reprimanding them. He means:

If you turn away, you will not harm him at all; rather, you harm yourselves. The Messenger is only responsible for what Allah has entrusted him with and commanded him regarding the delivery of the message. Once he has delivered it, he has fulfilled his obligation. As for you, you are responsible for what you have been commanded regarding receiving it with acceptance and submission. If you do not do so and turn away, you have exposed yourselves to the wrath of Allah and His punishment. If you obey him, you have secured your share of moving from misguidance to guidance. The benefit and harm return to you, and the Messenger is merely a sincere advisor and guide. It is upon him only to convey what is beneficial for your acceptance [[The phrase 'for your acceptance' is the wording of Al-Nasafi: 'in your hearts': (A)]] , and he is not harmed by your turning away:

And conveying means delivering, just as performing means fulfilling. The meaning of 'the clear' is being accompanied by the verses and miracles.