Amṛtanāda (Amṛtanādabindu) Upaniṣad 29

29

anena vidhinā samyaṅnityamabhyasataḥ kramāt |
svayamutpadyate jñānaṃ tribhirmāsairna saṃśayaḥ ||

(Then about the obstacles of yogi). A yogin should always avoid fear, anger, laziness, too much sleep or waking and too much food or fasting. If the above rule be well and strictly practised each day, spiritual wisdom will arise of itself in three months without doubt. In four months, he sees the ḍevas; in five months, he knows (or becomes) Brahmanishtha; and truly in six months he attains Kaivalya at will. There is no doubt.