Jānussoṇi visits the Buddha at Jetavana and asks him how it is that young men who have left the world under him should be able to live in solitude, in the depths of the forest, a joyless life. The Buddha answers that while yet a Bodhisatta he was assailed by the same doubts. Fear comes only to him whose heart is filled with desire and longing, and who is restless, witless, and driveling.
However, the man, who is pure, resolute, and free from corruptions of the heart, lives in confidence in the forest and develops the absorptions (jhāna). The Buddha then describes how he passed through these stages of development before becoming the Enlightened One (M.i.16 ﬀ).
This sutta contains an account of the threefold lore (tisso vijjā) of the Buddha (see Sp.i.116) and praises of the Three Refuges (tisaraṇā) (Sp.i.172).