Arthashastra
कालश् च सकृद् अभ्येति यं नरं काल काङ्क्षिणम् । दुर्लभः स पुनस् तस्य कालः कर्म चिकीर्षतः ॥
"An opportunity will only once offer itself to a man who is waiting for it, and will not come a second time when he may be desirous of accomplishing his work."
english translation
kAlaz ca sakRd abhyeti yaM naraM kAla kAGkSiNam । durlabhaH sa punas tasya kAlaH karma cikIrSataH ॥
hk transliteration by Sanscript