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.
That is the mission. When Lord Kṛṣṇa comes or any incarnation of Lord comes actually, not so-called advertised incarnation . . . I mean to say that you will find all the incarnation in the Vedic literature, they are named there, not that anyone can manufacture himself as incarnation.
Every incarnation is mentioned in the Vedic scripture, when and how, what kind of work he will do, and what place, which place, and everything in detail is there so that there is chart of the incarnation. Nobody can become an incarnation beyond that chart. There is chart. Just like there will be an incarnation of Kalki, I have several times spoken before you, which will take place about four millions of years later on. Still, His name is mentioned in the Bhāgavata, and the place is also mentioned. His father's name is also mentioned. This is called incarnation.
So Lord comes as incarnation for these two purposes: to protect the saintly persons and to annihilate the atheistic demons, and to establish the real purpose of religion. Now, the point was that what is the real purpose of religion? That real purpose of religion, now, Kṛṣṇa said that "I descend for establishing the purpose of religion." Yadā yadā hi dharmasya glānir bhavati, dharma-saṁsthāpanārthāya (BG 4.7). Paritrāṇāya sādhūnāṁ vināśāya ca duṣkṛtām (BG 4.8).