The Personality of Godhead Sri Krsna appeared before us just a little prior to the beginning of Kali-yuga, and He returned to His eternal home practically at the commencement of Kali-yuga. While He was present, He exhibited everything by His different activities. He spoke the Bhagavad-gita specifically and eradicated all pretentious principles of religiosity. And prior to His departure from this material world, He empowered Sri Vyasadeva through Narada to compile the messages of the Srimad-Bhagavatam, and thus both the Bhagavad-gita and the Srimad-Bhagavatam are like torchbearers for the blind people of this age. In other words, if men in this age of Kali want to see the real light of life, they must take to these two books only, and their aim of life will be fulfilled.

From Srila Prabhupada's purport to SB 1.3.43