Kautilya's Arthashastra 7.4.5

7.4.5

yadā vā paśyet "svadaṇḍair mitrāṭavīdaṇḍair vā samaṃ jyāyāṃsaṃ vā karśayitum utsahe" iti tadā kṛtabāhyābhyantarakṛtyo vigṛhyāsīta //

When a king finds it possible to put down by means of his own army, or with the help of a friend, or of wild tribes, another king of equal or superior power, then having set up proper defences against both internal and external enemies, he may keep quiet after proclaiming war.