Bhagavad Gita Chapter 2.66
nāsti buddhir ayuktasya
na cāyuktasya bhāvanā
na cābhāvayataḥ śāntir
aśāntasya kutaḥ sukham
Translation
One who is not connected with the Supreme [in Krishna consciousness] can have neither transcendental intelligence nor a steady mind, without which there is no possibility of peace. And how can there be any happiness without peace?