nāsti buddhir-ayuktasya na chāyuktasya bhāvanā
na chābhāvayataḥ śhāntir aśhāntasya kutaḥ sukham|| 66||

My Understanding : Peace is the state where your emotions are not swayed by good or bad circumstances. When you are free from such feelings, you remain unchanged regardless of the situation. Without peace, true happiness cannot be found in anything. All emotions are controlled by the senses, and if you can master control over them, you will find peace in everything.