नास्ति बुद्धिरयुक्तस्य न चायुक्तस्य भावना। न चाभावयतः शान्तिरशान्तस्य कुतः सुखम् ॥

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

There is no Pure Reason for the non-harmonised, nor for the non-harmonised is there concentration; for him without concentration there is no peace, and for the unpeaceful how can there be happiness?

In plain words: A person who is not self-controlled cannot think clearly or focus. Without focus there is no peace, and without peace there can be no real happiness.