Kautilya's Arthashastra 7.6.9

7.6.9

yadi vā manyeta "pravarṣoṣṇaśītam ativyādhiprāyam upakṣīṇāhāropabhogaṃ sainyavyāyāmānāṃ cauparodhikaṃ kāryasādhanānām ūnam atiriktaṃ vā kālaṃ paraś ceṣṭiṣyate, viparītam aham" ity etasmin viśeṣe paripaṇitakālaṃ saṃdhim upeyāt //

When the conqueror thinks that "my enemy has to work with food stuffs falling short and with no comfort during the rainy, hot or cold season, giving rise to various kinds of diseases and obstructing the free exercise of his army during a shorter or longer period of time than necessary for the accomplishment of the work in hand; and I have to work during a time of quite the reverse nature," then he should make time a factor of the agreement.