Arthashastra
अहि भयाद् अभ्यन्तर कोपो बाह्य कोपात् पापीयान् इत्य् उक्तं पुरस्ताद् ॥
for it has been already stated that internal troubles like the fear from a lurking snake are more serious than external troubles.
english translation
ahi bhayAd abhyantara kopo bAhya kopAt pApIyAn ity uktaM purastAd ॥
hk transliteration by Sanscript