ٱتَّبِعُوا۟ مَن لَّا يَسْـَٔلُكُمْ أَجْرًا وَهُم مُّهْتَدُونَ
Ittabi'oo mal-laa yas'alukum ajranw-wa hum muhtadoon
Follow them: they are not asking you to reward them and they are rightly guided.
Follow those who ask no reward of you and are rightly guided.
The speaker holds no office and arrives from the edge of the city, so what he offers his people is a test they can run for themselves: look at who is asking to be paid. It is the same measure the messengers of Ash-Shu'ara press on their own communities. Disinterest settles nothing about the content of a message, and it stays the one thing a listener can check before knowing anything else.