In plain words
If these good thoughts are not in us, Dharmayeva hatohanti. We destroy Dharma, but Dharma destroys us.
Today is the holy Guru Pūrṇimā. Gokak has told you about this Guru Pūrṇimā well, in a way that is easy to understand. Through certain kinds of books and through teachings, dispelling the darkness called Ajñāna in man and lighting the radiant lamp called Prajñāna. Now, the faith of the people of Bhārata is that by taking some guru as their support they will reach a higher state through his good teachings. Here there are many gurus. The gurus the śāstras approve are eight. The Bodha guru, the Veda guru, the Nihita guru, the Kāmya guru, the Vācaka guru, the Sūcaka guru, the Kāraṇa guru and the Vihita guru. There are these eight gurus. The Bodha guru teaches only the meaning of the śāstras and gives zeal and encouragement to follow their rules properly. The Veda guru is one who teaches the meaning of the principles, gives a vision of them, and turns one's mind towards God. The Nihita guru removes doubts of many kinds, purifies the mind, and through purity of citta makes one recognise one's own Ātma principle. The Niṣiddha guru teaches certain kāmya karmas and gives joy here and hereafter. The Kāmya guru has one perform meritorious deeds and so gives happiness here and hereafter. The Sūcaka guru teaches the noble wealth of śama, dama and the rest and has a man restrain his senses. Then the Vācaka guru. He teaches the principle of yoga and makes one experience the divine Ātma principle. The Kāraṇa guru brings about union with the oneness of jīva and Brahman. So the Kāraṇa guru alone is the chief guru. He is the one who can transform the principle of the jīva into the divine principle. He teaches that the relation between these two is the relation of an image and its reflection. He shows that there is no difference between the jīva and God. He gives teachings in the form of practice; He demonstrates direct proofs. This guru is God alone. So that very guru: Gurubrahma guruviṣṇuḥ gurudevo maheśvaraḥ tasmai śrī gurave namaḥ. He kept showing that one must regard Him alone as Brahmā, Viṣṇu and Maheśvara.
So, as Gokak said, all of us who belong to the world are teachers only, in certain matters; one cannot call them gurus.