432
Śrīmad-Bhāgavatam
[Canto 3, Ch. 11]
PURPORT
Every living being lives for one hundred years in terms of the times in different planets for different entities. These one hundred years of life are not equal in every case. The longest duration of one hundred years belongs to Brahmā, but although the life of Brahmā is very long, it expires in the course of time. Brahmā is also afraid of his death, and thus he performs devotional service to the Lord, just to release himself from the clutches of illusory energy. Animals, of course, have no sense of responsibility, but even humans, who have developed a sense of responsibility, while away their valuable time without engaging in devotional service to the Lord; they live merrily, unafraid of impending death. This is the madness of human society. The madman has no responsibility in life. Similarly, a human being who does not develop a sense of responsibility before he dies is no better than the madman who tries to enjoy material life very happily without concern for the future. It is necessary that every human being be responsible in preparing himself for the next life, even if he has a duration of life like that of Brahmā, the greatest of all living creatures within the universe.
TEXT 34
यदर्धमायुषस्तस्य परार्धमभिधीयते । 
    पूर्वः परार्धोऽपक्रान्तो ह्यपरोऽद्य प्रवर्तते ॥३४॥
yad ardham āyuṣas tasya 
    parārdham abhidhīyate 
    pūrvaḥ parārdho 'pakrānto 
    hy aparo 'dya pravartate
yat —that which;  ardham —half;  āyuṣaḥ —of the duration of life;  tasya —his;  parārdham —a  parārdha ;  abhidhīyate —is called;  pūrvaḥ —the former;  parārdhaḥ —half of the duration of life;  apakrāntaḥ —having passed;  hi —certainly;  aparaḥ —the latter;  adya —in this millennium;  pravartate —shall begin.
TRANSLATION
The one hundred years of Brahmā's life are divided into two parts, the first half and the second half. The first half of the duration of Brahmā's life is already over, and the second half is now current.