Arthashastra
यत्र बाह्या बाह्यान् उपजपन्ति, अभ्यन्तरान् अभ्यन्तरा वा, तत्र एकान्त योग उपजपितुः सिद्धिर् विशेषवती ॥
Where foreigners carry on an intrigue with foreigners, or local men with local men, there the consequences of the intrigue, unanimously carried on with a set purpose, will be very serious.
english translation
yatra bAhyA bAhyAn upajapanti, abhyantarAn abhyantarA vA, tatra ekAnta yoga upajapituH siddhir vizeSavatI ॥
hk transliteration by Sanscript