One of the things which offends us about radio and TV commercials is that it is often perfectly evident from the tone of voice that the announcer is “putting on”, playing a role, saying something he doesn’t feel. This is an example of incongruence. On the other hand each of us knows individuals whom we somehow trust because we sense that they are being what they are, that we are dealing with the person himself, not with a polite or professional front. It is this quality of congruence which we sense which research has found to be associated with successful therapy.
— What We Know About Psychotherapy — Objectively and Subjectively, from On Becoming a Person (1961)
Congruence is a combination of calm, positive acceptance with honesty, sincerity, and spontaneity, that has gone far enough to become a default habit in a person and their communication. There is then not such a gap between “should” and “is”. This acceptance beams itself to others who entrain to the person in a process of spontaneous change, sparking a way of being in turn that is comfortable for them, naturally generating ideas that support such self-acceptance. This is the process of Rogerian therapy. Because meditation also establishes calm acceptance, the process can be adapted for meditators.
The importance of congruence in therapeutic success (far greater than that of “theory” and other intellectual factors) has again been demonstrated consistently and repeatedly since Rogers’ time. It can be considered entirely research-validated.