Kautilya's Arthashastra 9.3.1

9.3.1

alpaḥ paścātkopo mahān purastāllābha iti alpaḥ paścātkopo garīyān //

OF the two things, slight annoyance in the rear, and considerable profit in the front, slight annoyance in the rear is more serious; for traitors, enemies, and wild tribes augment on all sides the slight annoyance which one may have in the rear. The members of one's own state may be provoked about the acquisition of considerable profit in the front.