SB 7.13.10
avyakta-lingo vyaktartho
manisy unmatta-balavat
kavir mukavad atmanam
sa drstya darsayen nrnam
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Although a saintly person may not expose himself to the vision of human society, by his behavior his purpose is disclosed. To human society he should present himself like a restless child, and although he is the greatest thoughtful orator, he should present himself like a dumb man.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
A great personality very much advanced in Krsna consciousness may not expose himself by the signs of a sannyasi. To cover himself, he may live like a restless child or a dumb person, although he is the greatest orator or poet.