Virtuous, wise aspirant; pious or righteous person. (Glossary for the Vahinis)

‘Sadhu’ means ‘good’. Sadhu virtues might be found even in animals and insects and worms.

(SSS Vol.2, p. 141)

Through good thoughts and holy ideas only, one will become a Sadhu. By Sadhu, it is not meant one who dons a saffron robe and has a clean-shaven head and wears Rudraksha-malas on his neck. Sadhu really means one who is filled with holy ideas, who has become a ‘Satya Sankalpa Swarupa - embodiment of all pure and holy ideas. (TTFFW,  p. 11)

Really speaking, the promotion of Sattva guna is the best means of fostering Sadhus. (GV, p.66)

A Sadhu is he who does not deviate from his duty, whatever the temptation and whatever the danger. (GV, p. 67)

Your real companions from whom you derive the maximum good are those who talk and discourse about the Lord, about Truth, about the Seva of others and about Prema that considers all as equal. Association with such people is certainly association with Sadhus, for these are the real Sadhus. (DhyV, p. 49)

All those who follow Sadachara, who have Satshila, who adhere to Satya, who yearn for the Samadhi (Presence) of Sarveshvara (the Lord), who observe Saddharma, who consider sarvajana (all) as Samana... (equal) all of them are Sadhus. (GV, p. 60)

You must see the Divine in everyone. This is the true trait of a ‘Sadhu’. The wearing of the ochre robe does not make a man a ‘Sadhu’. He must possess the qualities of a ‘Sadhu’. He must be pure hearted. Transformation of the heart is what is called for. All that you do should lead you nearer to god. When you act in this way, nothing bad will touch you. (AV, p.168)

The distinction made between householders and sannyasis is not of real significance. The wearing of the ochre robe alone will not make a man a devotee of God. By the mere mouthing of mantras one’s sins will not be washed away. Carrying the Gita and shouting slogans will not make one meritorious. Only the man whose thoughts and deeds are in harmony can be called a Sadhu (a saintly person). Who are Sadhus? Not merely those who don the ochre robe. All are Sadhus. All beings have sadhutva (goodness and purity) inherent in them. They have to foster and manifest these qualities and not the external vesture. It is the purity of one’s thoughts which reveal his sadhutva.

There is no need to put on the orange robe to become a Sadhu. The heart must be pure. Ravana put on a guise of an ascetic to kidnap Sita. His garb only concealed his evil intent. It is the evil qualities that have to be given up.

Even if the process is begun in a small way, it will result in great good. The start must be made when one is young. (SSS Vol.21, pp. 8-9)