This verse is from the Bhagavad Gita, Chapter 6, Verse 15. It is written in Sanskrit and translates to English as follows:
yuñjann evaṁ sadātmānaṁ yogī niyatamānasaḥ
śāntiṁ nirvāṇa-paramāṁ mat-saṁsthām adhigacchati || 15 ||
"Thus, engaging always in the self, the yogi with a controlled mind attains peace which is the supreme nirvana, and abides in Me."
This verse emphasizes the importance of a disciplined and concentrated mind for a yogi. By continuously focusing on the self and maintaining mental discipline, the yogi can achieve ultimate peace, leading to liberation (nirvana) and union with the divine.
yuñjan: engaging (in meditation)
evam: thus
sadā: always
ātmānam: the self
yogī: the yogi
niyata-mānasaḥ: with a controlled mind
śāntim: peace
nirvāṇa-paramām: the supreme nirvana (liberation)
mat-saṁsthām: situated in Me
adhigacchati: attain