Jesus uses irony to condemn the Phraisees because they think of themselves as righteous. Anyone who wants to follow Jesus has to think of himself as a sinner, not as righteous. Jesus does not mean that he thinks there are righteous people who do not need to repent. (See: [[rc://en/ta/man/translate/figs-irony]])
This nominal adjective can be translated as a noun phrase. Alternate translation: "righteous people" (See: [[rc://en/ta/man/translate/figs-nominaladj]])