Kautilya's Arthashastra 9.1.52

9.1.52

sarvā vā hrasvakālāḥ syur yātavyāḥ kāryalāghavāt /
dīrghāḥ kāryagurutvād vā varṣāvāsaḥ paratra ca //E

When the work to be accomplished is small, march against all kinds of enemies should be of short duration; and when it is great, it should also be of long duration; during the rains, encampment should be made abroad.