Arthashastra
"प्रभूतं मे मित्र बलं शक्यं मूले यात्रायां च आधातुम्ण्" "अल्पः प्रवासो मन्त्र युद्धाच् च भूयो व्यायाम युद्धम्ण्" "मित्र बलेन वा पूर्वम् अटवीं नगर स्थानम् आसारं वा योधयित्वा पश्चात् स्व बलेन योद्धयिष्यामिण्" "मित्र साधारणं वा मे कार्यम्ण्" "मित्र आयत्ता वा मे कार्य सिद्धिह्ण्" "आसन्नम् अनुग्राह्यं वा मे मित्रम्ण्" "अत्यावापं वा अस्य सादयिष्यामि" इति मित्र बल कालः ॥
When he thinks that the strong help he has in his friend can be made use of both in his own country and in his marches; that he has to be absent only for a short time, and actual fight is more than treacherous fight; that having made his friend's army to occupy wild tracts, cities, or plains and to fight with the enemy's ally, he, himself, would lead his own army to fight with the enemy's army; that his work can be accomplished by his friend as well; that his success depends on his friend; that he has a friend near and deserving of obligation; or that he has to utilize the excessive force of his friend, then is the time for the enlistment of a friend's army.
english translation
"prabhUtaM me mitra balaM zakyaM mUle yAtrAyAM ca AdhAtumN" "alpaH pravAso mantra yuddhAc ca bhUyo vyAyAma yuddhamN" "mitra balena vA pUrvam aTavIM nagara sthAnam AsAraM vA yodhayitvA pazcAt sva balena yoddhayiSyAmiN" "mitra sAdhAraNaM vA me kAryamN" "mitra AyattA vA me kArya siddhihN" "Asannam anugrAhyaM vA me mitramN" "atyAvApaM vA asya sAdayiSyAmi" iti mitra bala kAlaH ॥
hk transliteration by Sanscript