Bg. 2.54

As there are symptoms for each and every man, in terms of his particular situation, similarly one who is Kṛṣṇa conscious has his particular nature – talking, walking, thinking, feeling, etc. As a rich man has his symptoms by which he is known as a rich man, as a diseased man has his symptoms by which he is known as diseased, or as a learned man has his symptoms, so a man in transcendental consciousness of Kṛṣṇa has specific symptoms in various dealings. One can know his specific symptoms from the Bhagavad-gītā. Most important is how the man in Kṛṣṇa consciousness speaks; for speech is the most important quality of any man. It is said that a fool is undiscovered as long as he does not speak, and certainly a well-dressed fool cannot be identified unless he speaks, but as soon as he speaks, he reveals himself at once. The immediate symptom of a Kṛṣṇa conscious man is that he speaks only of Kṛṣṇa and of matters relating to Him. Other symptoms then automatically follow, as stated below.