kṣīṇa-āyuṣaḥ - their life span diminished; kṣīṇa-sattvān - their strength diminished; durmedhān - of less intelligence; vīkṣya - observing; kālataḥ - by the effect of time; vedān - the Vedas; brahma-ṛṣayaḥ - the chief sages; vyasyan - divided up; hṛdi-stha - sitting within their hearts; acyuta - by the infallible Personality of Godhead; coditāḥ - inspired.

Observing that people in general were diminished in their life span, strength and intelligence by the influence of time, great sages took inspiration from the Personality of Godhead sitting within their hearts and systematically divided the Vedas.