Meaning
Supreme God Krishna spoke
Imbued with purified intellect, regulating the self through {Noble, Sāttvic} holding power of mind, restraining or forsaking the objects of senses like speech, etc. (i.e., observing silence and meditating in silence), casting away likes and dislikes, (18:51)
Residing in seclusion with frugal eating habits, keeping control over speech, body, and mind, remaining dedicated to Meditative Yoga practicing constant dispassion, (18:52)
And, by renouncing ego, aggression, vanity, carnal desire, anger, possessions, and the sense of "me and mine," one attains inner calm and becomes worthy of merging into Brahm. (18:53)
Sanskrit
श्रीभगवान् उवाच
बुद्ध्या विशुद्धया युक्तो धृत्यात्मानं नियम्य च ।
शब्दादीन्विषयांस्त्यक्त्वा रागद्वेषौ व्युदस्य च ॥
Word-by-word
बुद्ध्या विशुद्धया युक्तः, धृत्या आत्मानम् नि-यम्य च,
शब्द-आदीन् विषयान् त्यक्त्वा, राग-द्वेषौ व्युदस्य च;