Bhagavad Gita 6.14
With peace in his heart and no fear, observing the vow of celibacy, with his mind controlled and fixed on Me, let the student lose himself in contemplation of Me.
प्रशान्तात्मा विगतभीर्ब्रह्मचारिव्रते स्थितः।
मनः संयम्य मच्चित्तो युक्त आसीत मत्परः॥praśāntātmā vigatabhīrbrahmacārivrate sthitaḥ|
manaḥ saṃyamya maccitto yukta āsīta matparaḥ||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).