If an opportunity, with respect to the man who waits for it, once goes away it can never be secured again by the person desirous of acting.
यो हि कालो व्यतिक्रामेत् पुरुषं कालकाक्षिणम्। दुर्लभः स पुनस्तेन कालः कर्मचिकीर्षुणा॥