It is said by Canakya Pandita that a rascal appears very intelligent as long as he does not speak. But speaking is the test
SB Canto 3
The sage Kardama accepted silence as a vow in order to think of the Supreme Personality of Godhead and take shelter of Him exclusively. Without association, he traveled over the surface of the globe as a sannyāsī, devoid of any relationship with fire or shelter.
Here the words anagnir aniketanaḥ are very significant. A sannyāsī should be completely detached from fire and any residential quarters. A gṛhastha has a relationship with fire, either for offering sacrifices or for cooking, but a sannyāsī is freed from these two responsibilities. He does not have to cook or offer fire for sacrifice because he is always engaged in Kṛṣṇa consciousness; therefore he has already accomplished all ritualistic performances of religion. Aniketanaḥ means "without lodging." He should not have his own house, but should depend completely on the Supreme Lord for his food and lodging. He should travel.
Mauna means "silence." Unless one becomes silent, he cannot think completely about the pastimes and activities of the Lord. It is not that because one is a fool and cannot speak nicely he therefore takes the vow of mauna. Rather, one becomes silent so that people will not disturb him. It is said by Cāṇakya Paṇḍita that a rascal appears very intelligent as long as he does not speak. But speaking is the test. The so-called silence of a silent impersonalist svāmī indicates that he has nothing to say; he simply wants to beg. But the silence adopted by Kardama Muni was not like that. He became silent for relief from nonsensical talk. One is called a muni when he remains grave and does not talk nonsense. Mahārāja Ambarīṣa set a very good example; whenever he spoke, he spoke about the pastimes of the Lord. Mauna necessitates refraining from nonsensical talking, and engaging the talking facility in the pastimes of the Lord. In that way one can chant and hear about the Lord in order to perfect his life. Vratam means that one should take a vow as explained in Bhagavad-gītā, amānitvam adambhitvam, without hankering for personal respect and without being proud of one's material position. Ahiṁsā means not being violent. There are eighteen processes for attaining knowledge and perfection, and by his vow, Kardama Muni adopted all the principles of self-realization.