Manusmriti

siva.sh/manusmriti/9/298

चारेणोत्साहयोगेन क्रिययैव च कर्मणाम् । स्वशक्तिं परशक्तिं च नित्यं विद्यान्महीपतिः ॥ २९८ ॥

sanskrit

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