In plain words
Embodiments of Prema! The destiny of every living being is precisely to attain fullness. However many births it takes and in whatever way it lives, in the end it must reach that state without fail. When, and how: that rests on the karma of past births, and it takes its shape from the feelings that lie behind that karma. Today's condition is nothing but the fruit of karma and feeling. The fruit of today's karma and feeling is the future. We ourselves are the makers of our fortune. Do these tasks of shaping our fortune need the help of others? To reach the lofty height of the full spiritual state, the help of others is indeed needed. It is not something gained from reading books. It is a growth that comes from the ties of relationship and kinship that must pass from one heart to another.
Poring over books makes argument and counter-argument grow. Through the Buddhi, strength and ability can grow; but to step forward on the spiritual path, experiences alone are the chief thing. To bring such experiences about in the heart, to root out hardened Ajñāna, to receive the divine spiritual influence, the Guru is utterly necessary. It can only come straight from one jīva to another. Full and sacred Jñāna of the Ātma cannot be had without a Guru. Among Gurus there are many kinds: the dīkṣā Guru and the śikṣā Guru, as they are called. To say that one who has given a mantra is a Guru is simply to misunderstand the word. That is an ancient tradition. While chanting the mantra, many people forget the divinity within themselves. But the Guru whom crores upon crores of voices have praised through the generations is one who gave the disciple training, shaped him, and rooted out his darkness. 'Gu' means the darkness of Ajñāna; 'ru', its removal. Precisely this is the inner meaning of Guru Pūrṇimā. Pūrṇimā means the principle of fullness. The principle of the Ātma itself. That transcendent principle of fullness. Pūrṇa means fullness in the nature of guṇa, fullness in Quality. A big lump of sugar is sweet; even a speck of it is the same sweetness. To know the taste of the unfathomable, bottomless ocean you need not drink it all; it is enough to put one drop in your mouth. In the fathomless form and in the atomic form alike, the Paramātma is uniformly of the very nature of Sat-Cit-Ānanda. This is Sat-Cit-Ānanda itself; even a drop taken from it is that same Sat-Cit-Ānanda. The immense form. The atomic form: both are full indeed. The Ātma within human beings and the Paramātma are both full in their very svarūpa.
Today is the full moon, and in the full moon no spot is seen. Whiteness and coolness stand foremost; the spots called Ajñāna and darkness — in the moon that is the symbol of the Manas, the divinity within the Manas can shine forth in full today. What kind of person should the Guru be? He must shine with Bhakti and prapatti, with forbearance and Śānti, with full radiance.