Kautilya's Arthashastra 9.1.1

9.1.1

vijigīṣur ātmanaḥ parasya ca balābalaṃ śaktideśakālayātrākālabalasamuddānakāla.paścātkopakṣayavyayalābhāpadāṃ jñātvā viśiṣṭabalo yāyāt, anyathāsīta //

THE conqueror should know the comparative strength and weakness of himself and of his enemy; and having ascertained the power, place, time, the time of marching and of recruiting the army, the consequences, the loss of men and money, and profits and danger, he should march with his full force; otherwise, he should keep quiet.