Manusmriti
चारेणोत्साहयोगेन क्रिययैव च कर्मणाम् । स्वशक्तिं परशक्तिं च नित्यं विद्यान्महीपतिः ॥ २९८ ॥
By spies, by a (pretended) display of energy, and by carrying out (various) undertakings, let the king constantly ascertain his own and his enemy’s strength;
english translation
cAreNotsAhayogena kriyayaiva ca karmaNAm । svazaktiM parazaktiM ca nityaM vidyAnmahIpatiH ॥ 298 ॥
hk transliteration by Sanscript