Kautilya's Arthashastra 7.5.39

7.5.39

śaktimān hi pārṣṇigrahaṇe yātrāsāhāyyadāne vā śaktaḥ, śuciḥ siddhau cāsiddhau ca yathāsthitakārīti //

‘A king of considerable power,’ means one who is strong enough to put down or capture an enemy in the rear of his friend or to give sufficient help to his friend in his march.

‘A king of righteous character,’ means one who does what one has promised to do, irrespective of good or bad results.