Tafsir of Ad-Dhariyat 51:53

"Did they exhort one another to it?" This is an expression of astonishment at their consensus upon that heinous statement. That is, it is as if the first and the last of them exhorted one another to say this statement, until they all said it. It has also been said that it is a denial of any mutual exhortation—meaning, they did not exhort one another to it.

"Nay, but they are a transgressing people." This is a retraction from the suggestion that mutual exhortation brought them together, to the clarification that what brought them together upon that statement was their shared transgression, which is what compelled them toward it.