SB 1.16.25

dharany uvaca
bhavan hi veda tat sarvam
yan mam dharmanuprcchasi
caturbhir vartase yena
padair loka-sukhavahaih

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:

The earthly deity [in the form of a cow] thus replied to the personality of religious principles [in the form of a bull]: O Dharma, whatever you have inquired from me shall be known to you. I shall try to reply to all those questions. Once you too were maintained by your four legs, and you increased happiness all over the universe by the mercy of the Lord.

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:

The principles of religion are laid down by the Lord Himself, and the executor of such laws is Dharmaraja, or Yamaraja. Such principles work fully in the age of Satya-yuga; in the Treta-yuga they are reduced by a fraction of one fourth; in the Dvapara-yuga they are reduced to one half, and in the Kali-yuga they are reduced to one fourth, gradually diminishing to the zero point, and then devastation takes place. Happiness in the world depends proportionately on the maintenance of the religious principles, individually or collectively. The best part of valor is to maintain the principles despite all kinds of odds. Thus one can be happy during the span of life and ultimately return to Godhead.