योगवासिष्ठः yogavāsiṣṭhaḥ - book-7, chapter-211, verse-13

किंतु ते स्थिरतां नीताः सिद्धैः स्वर्यानसंपदा ।
अस्थिरैर्ध्यानविश्रान्तौ तैर्दुःखैस्तदमी कृताः ॥ १३ ॥

kiṃtu te sthiratāṃ nītāḥ siddhaiḥ svaryānasaṃpadā ,
asthirairdhyānaviśrāntau tairduḥkhaistadamī kṛtāḥ 13

13. Now as men of steady minds, find themselves to be soaring to heaven, in the company of the siddhas and clad in all their glory; those of fickle and unsubdued minds, have to take great pains, in order to confine the fleeting object of their contemplation under their control.