SB 3.30.1

kapila uvāca
tasyaitasya jano nūnaṁ
 nāyaṁ vedoru-vikramam
kālyamāno ’pi balino
 vāyor iva ghanāvaliḥ
Word for word: 
kapilaḥ uvāca — Lord Kapila said; tasya etasya — of this very time factor; janaḥ — person; nūnam — certainly; na — not; ayam — this; veda — knows; uru-vikramam — the great strength; kālyamānaḥ — being carried off; api — although; balinaḥ — powerful; vāyoḥ — of the wind; iva — like; ghana — of clouds; āvaliḥ — a mass.
Translation: 
The Personality of Godhead said: As a mass of clouds does not know the powerful influence of the wind, a person engaged in material consciousness does not know the powerful strength of the time factor, by which he is being carried.
Purport: 

The great politician-paṇḍita named Cāṇakya said that even one moment of time cannot be returned even if one is prepared to pay millions of dollars. One cannot calculate the amount of loss there is in wasting valuable time. Either materially or spiritually, one should be very alert in utilizing the time which he has at his disposal. A conditioned soul lives in a particular body for a fixed measurement of time, and it is recommended in the scriptures that within that small measurement of time one has to finish Kṛṣṇa consciousness and thus gain release from the influence of the time factor. But, unfortunately, those who are not in Kṛṣṇa consciousness are carried away by the strong power of time without their knowledge, as clouds are carried by the wind.