Here is the Sutta from PTS Gradual Sayings Vol. 1, page 67.
[ The book of twos, chapter V, #4]
"Monks, there are these two companies. What two? The Ariyan and the
un-Ariyan (1). And what, monks, is the un-Ariyan company?
Herein, monks, in whatsoever company the monks understand not, as it
really is, the meaning of "This is suffering"; understand not, as it
really is, the meaning of "This is the arising of suffering"; understand
not, as it really is, the meaning of "This is the ending of suffering";
understand not ... "This is the practice leading to the ending of
suffering", - this company is called "the un-Ariyan."
And what, monks is the Ariyan company? (The reverse of the above).
..... These are the two companies, and of these two the Ariyan company
has the pre-eminence.
Footnote 1. Comy, distinguishes them as "that of noble disciples" and
"that of the ordinary persons".
[ I have made some minor changes, such as replacing "Ill" with "suffering".]