BG 2.53-55
When thy mind, bewildered by the Scriptures, shall stand immovable, fixed in contemplation, then shalt thou attain unto yoga. Arjuna said: What the mark, of him who is stable of mind, steadfast in contemplation, O Keshava? How doth the stable-minded talk, how doth he sit, how walk? The Blessed Lord said: When a man abandoneth, O Pârtha, all the desires of the heart, and is satisfied in the Self by the Self, then is he called stable in mind.