MN 122 Greater Discourse on Voidness: Maha-sunnyata
The Buddha finds Ananda living with a lot of monks. ‘Ananada, a bikkhu does not shine by taking delight in company’. One who does so can’t attain the bliss of renunciation, seclusion, peace or enlightenment.
‘I do not see even a single form, Ananda, from the change and alteration of which there would not arise sorrow […] and despair in one who lusts for it and takes delight in it.’
‘However, Ananda, there is this abiding discovered by the Tathagata: to enter and abide in voidness internally by giving no attention to all signs’.
A teacher a student and one leading the holy life can all be undone by taking delight in company. They revert to luxury and succumb to craving.