In plain words
Prema for God. Service to Him is itself Bhakti. That is why ‘Ṛṣikeśa sevanaṃ bhaktirucyate,’ said Nārada. Making the Name of God dance on the tongue, developing friendship with God from day to day and making it firm, as this maitrī becomes our mainstay and the close kinship between God and devotee grows, karuṇā arises in us through this maitrī. Through this karuṇā, upekṣā. With no hatred, delusion or attachment towards anyone, he experiences Ānanda in a divine feeling. That is why good company is most needed for this Bhakti. Through this good company, the seed of Prema that has sprouted in us grows day by day. As these four, maitrī, karuṇā, muditā and upekṣā, all grow, one-pointedness of the citta comes about. So one-pointedness of the citta is attained through Bhakti. By karma, purity of citta; by Bhakti, one-pointedness of the citta.
Now the third, Jñāna. What is Jñāna? There are many kinds of knowledge. Worldly knowledge, physical knowledge, is one. Mere general knowledge is another. Ordinary cleverness. But these are not physical. This is Ātma-Jñāna. It is not inquiry only about the body, or about the senses, or about objects, or about any other kind of Prakṛti. By making such physical inquiries, only physical things come into our view. But when we go deep into the spiritual and inquire, we understand this Ātma-Jñāna to some extent. This Ātma-Jñāna cannot be taught by gurus. It cannot be had by reading books; nor is it a thing one receives when another gives it. It must arise from one's own antaḥkaraṇa. Gurus or books may teach it to some extent. But if the person who is to practise it is to bring it into experience, he must inquire by himself. He must carry out many kinds of inquiry within himself. He must examine closely. He must investigate. He must stand steady in his examination. A mother has a child. When she wants to teach the children words, the mother says with her own mouth, ‘Amma, appa.’ Watching the mother's mouth, the child learns ‘amma, appa’. But if, to teach the child words, the mother put her mouth in the child's mouth and told it to say ‘Ammā’, it could not say it. In the same way, gurus too can voice the things they have heard and the things they have seen through books, through the Vedas, through the Upaniṣads; but the jñānī must make it arise by himself alone. What is this Ātma-Jñāna? They said that the vision of Advaita is Jñāna.