SB 10.69.30
dhyayantam ekam asinam
purusam prakrteh param
susrusantam gurun kvapi
kamair bhogaih saparyaya
Translation:
Somewhere He was sitting alone, meditating on the Supreme Personality of Godhead, who is transcendental to material nature, and somewhere He was rendering menial service to His elders, offering them desirable things and reverential worship.
Purport:
Srila Prabhupada comments: “Meditation, as recommended in authorized scripture, is meant for concentrating one’s mind on the Supreme Personality of Godhead, Visnu. Lord Krsna is Himself the original Visnu, but because He played the part of a human being, He taught us definitely by His personal behavior what is meant by meditation.”
This activity of meditation indicates the brahma-muhurta, the early morning hours before sunrise.