Bhagavad Gītā Chapter Six verse 27

प्रशान्तमनसं ह्येनं योगिनं सुखमुत्तमम् ।
उपैति शान्तरजसं ब्रह्मभूतमकल्मषम् ॥

praśānta-manasaṃ hy enaṃ yoginaṃ sukham uttamam ।
upaiti śānta-rajasaṃ brahma-bhūtam akalmaṣam ॥

praśānta - serene, tranquillized, calm, quiet, composed, indifferentmanas - mind; that which objects of sense affect; the faculty or instrument through which thoughts enteryogin - a follower of the yoga systemsukha - pleasure; happiness; agreeable; ease; comfortable; pleasantuttama - most elevated, principal; uppermost, highest, chief; best, excellentśānta - quiescent; appeased, pacified, tranquil, calm, free from passions, undisturbed; abated, subsided, ceased, stopped, extinguished, averted; gentle, mild, friendly, kind, auspiciousrajas - excitingbrahma - the one self-existent spirit, the absolute; name of one of the principal hindu deities; referred to as the creator within the triple deity of supreme divinitybhūta - material element, one of the 5 elements; that which is or exists, any living being; being or being like anything, consisting of, mixed or joined with