Only the excellent gurus who have the power to discern such a vessel, the heart, are true gurus. Brother-in-law! They must be like an alarm clock to the disciple asleep in the sleep of ajñāna. If instead the guru is a miser and the disciple a sluggard, hell alone is the refuge of both.” In this way Kṛṣṇa Paramātma taught Arjuna well the qualifications of guru and disciple, their conduct, their knowledge of the śāstras and their experience, the qualities and marks they must have, and their faith and behaviour.