Yes, but the NT teaches both to the congregations and the body of Christ. There will be those in the congregations that believed that they are saved, but are not, and they are warned that their behavior is out of line with following Christ. Likewise, there are those who believe, but have doubts, and they are encouraged that they can be assured of their salvation.
Can we distinguish between the two? Partially, but their outward behavior, but not completely. Therefore, it is necessary to preach and to teach to both.
... by their outward behavior ...