2
Śrīmad-Bhāgavatam
[Canto 7, Ch. 6]
śrī-prahrāda uvāca 
  kaumāra ācaret prājño 
  dharmān bhāgavatān iha 
  durlabhaṁ mānuṣaṁ janma 
  tad apy adhruvam arthadam
śrī-prahrādaḥ uvāca—Prahlāda Mahārāja said;  kaumāraḥ —in the tender age of childhood;  ācaret —should practice;  prājñaḥ —one who is intelligent;  dharmān —occupational duties;  bhāgavatān —which are devotional service to the Supreme Personality of Godhead;  iha —in this life;  durlabham —very rarely obtained;  mānuṣam —human;  janma —birth;  tat —that;  api —even;  adhruvam —impermanent, temporary;  artha-dam —full of meaning.
TRANSLATION
Prahlāda Mahārāja said: One who is sufficiently intelligent should use the human form of body from the very beginning of life—in other words, from the tender age of childhood—to practice the activities of devotional service, giving up all other engagements. The human body is most rarely achieved, and although temporary like other bodies, it is meaningful because in human life one can perform devotional service. Even a slight amount of sincere devotional service can give one complete perfection.
PURPORT
The whole purpose of Vedic civilization and of reading the  Vedas  is to attain the perfect stage of devotional service in the human form of life. According to the Vedic system, therefore, from the very beginning of life the  brahmacarya  system is introduced so that from one's very childhood—from the age of five years—one can practice modifying one's human activities so as to engage perfectly in devotional service. As confirmed in  Bhagavad-gītā  (2.40),  svalpam apy asya dharmasya trāyate mahato bhayāt : "Even a little advancement on this path can protect one from the most dangerous type of fear." Modern civilization, not referring to the verdicts of Vedic literature, is so cruel to the members of human society that instead of teaching children to become  brahmacārīs ,