Kautilya's Arthashastra 7.7.2

7.7.2

sāmantaṃ sāmantena sambhūya yāyāt, yadi vā manyeta "pārṣṇiṃ me na grahīṣyati, pārṣṇigrāhaṃ vārayiṣyati, yātavyaṃ nābhisariṣyati, baladvaiguṇyaṃ me bhaviṣyati, vīvadhāsārau me pravartayiṣyati, parasya vārayiṣyati, bahvābādhe me pathi kaṇṭakān mardayiṣyati, durgāṭavyapasāreṣu daṇḍena cariṣyati, yātavyam aviṣahye doṣe saṃdhau vā sthāpayiṣyati,
labdhalābhāṃśo vā śatrūn anyān me viśvāsayiṣyati" iti //

Having combined with a neighbouring king, the conqueror may march against another neighbouring king. Or if he thinks that "(my enemy) will neither capture my rear nor make an alliance with my assailable enemy against whom I am going to march; (for otherwise) I shall have to fight against great odds; (my ally) will not only facilitate the collection of my revenue and supplies and put down the internal enemies who are causing me immense trouble, but also punish wild tribes and their followers entrenched in their strongholds, reduce my assailable enemy to a precarious condition or compel him to accept the proffered peace, and having received as much profit as he desires, he will endeavour to endear my other enemies to me," then the conqueror may proclaim war against one and make peace with another and endeavour to get an army for money or money for the supply of an army from among his neighbouring kings.