Sādhu, one who is called sādhu . . . sādhu means titikṣavaḥ. Titikṣavaḥ means very tolerant, very tolerant, very much tolerant. Titikṣavaḥ kāruṇikāḥ. At the same time, very kind-hearted. We find these two characters in the life of Lord Jesus. He was very much tolerant, at the same time kind to the people in general. You see?
So, titikṣavaḥ kāruṇikāḥ suhṛdaḥ sarva-bhūtānāṁ. And he is friend. A sādhu is friend of all living entities. He is not only friend of the humankind; he is friend of the animals, he is friend of the trees, he is friend of the ants, worms, reptiles, serpents—everyone. Titikṣavaḥ kāruṇikāḥ suhṛdaḥ sarva-bhūtānāṁ.
And ajāta-śatru. And because he is friend of everyone, he has no enemy. But unfortunately the world is so infidel, even to such a sādhu there is enemy. Just like Lord Jesus Christ had some enemies, and Mahatma Gandhi had also some enemies so who killed him. So the world is such treacherous, even a sādhu, he has some enemies. You see? But sādhu, from his side, he has no enemy. He is friend of everyone. Titikṣavaḥ kāruṇikāḥ suhṛdaḥ sarva-bhūtānāṁ (SB 3.25.21). And ajāta-śatravaḥ śāntāḥ, always peaceful. These are the qualities of sādhu, saintly persons.
So Lord comes down. Paritrāṇāya sādhūnām (BG 4.8). His special purpose of coming down as incarnation is to save the sādhus, because sādhus are always persecuted by the demons, the demonic class, the atheist class. They are always prepared to persecute the sādhus. The Lord comes—paritrāṇāya sādhūnām—just to protect the sādhus, or the saintly persons, and vināśāya ca duṣkṛtām, and to vanquish the miscreants.