A Sadhu (a true holy man) is one in whom the following excellences are found: even-mindedness towards all including friend, enemy and neutral; desirelessness; control of the senses in respect of external objects; abandonment of the three eshanas (desire for children, for wealth, and for heavenly enjoyment); placidity of mind arising from complete self-mastery; supreme devotion to Thee; equanimity of mind in success and failure; absence of all attachments; abandonment of all evil and selfish actions; abiding interest in contemplating on Brahman; the practices of Yama and other disciplines of Yoga; and satisfaction with whatever means of livelihood that comes spontaneously without seeking. Such are the characteristics of holy men. Intimate contact with them gives rise to delight in matters dealing with the Divine excellences and accounts.
Adhyatma Ramayana- Aranya Kandam Ch. 3 Verse 38-40