Vasiṣṭha's teaching (Mahārāmāyaṇa) 3.60.29

3.60.29

bhavatīti mahābāho yathāsaṃvedanaṃ jagat .
anabhyastāḥ padārthā ye śāstrapāṭhajapādayaḥ .. 29

28. [Sanskrit available] The bitter seems to be sweet, by being thought to be so; and what is unfavorable, becomes favorable as that which is friendly comes to be unfriendly by being taken in their contrary senses. (The mind can make a heaven of hell and a hell of a heaven. Milton).

29. [Sanskrit available] Thus Rama! it is by habitual meditation, that we gain the abstract knowledge of things; as on the other hand we forget what we learnt, by want of their recapitulation. (Habit is second nature, and practice is the parent of productions).