śrī-bhagavān uvāca
vanaṁ vivikṣuḥ putreṣu
bhāryāṁ nyasya sahaiva vā
vana eva vasec chāntas
tṛtīyaṁ bhāgam āyuṣaḥ
śrī-bhagavān uvāca - the Supreme Personality of Godhead said; vanam - the forest; vivikṣuḥ - desiring to enter; putreṣu - among the sons; bhāryām - wife; nyasya - entrusting; saha - together with; eva - indeed; vā - or; vane - in the forest; eva - certainly; vaset - one should dwell; śāntaḥ - with a peaceful mind; tṛtīyam - the third; bhāgam - division; āyuṣaḥ - of life.
In Kali-yuga a human being generally cannot live more than one hundred years, and even this is becoming most unusual. A man who has a reasonable expectation of living for one hundred years may adopt the vānaprastha order at the age of fifty, and then at the age of seventy-five he may take sannyāsa for complete renunciation. Since in Kali-yuga very few people live for one hundred years, one should adjust the schedule accordingly. Vānaprastha is intended as a gradual transition from materialistic family life to the stage of complete renunciation.