Srimad Bhagavatam Canto 10, Chapter 51, Text 19

SB 10.51.19

kalo baliyan balinam
 bhagavan isvaro ’vyayah
prajah kalayate kridan
 pasu-palo yatha pasun
“Inexhaustible time, stronger than the strong, is the Supreme Personality of Godhead Himself. Like a herdsman moving his animals along, He moves mortal creatures as His pastime.
The universe is created to gradually rectify the contaminated souls trying to exploit material nature. The Lord moves the conditioned souls along, according to their karma, through the various stages of spiritual rectification. Thus the Lord is like a herdsman (the word pasu-pala literally means “protector of animals”), who moves the creatures under his protection to various pastures and watering spots in order to protect them and sustain them. A further analogy is that of a doctor, who moves the patient under his care to various areas of a hospital for diverse kinds of examination and treatment. Similarly, the Lord brings us through the network of material existence in a gradual cleansing process so that we can enjoy our eternal life of bliss and knowledge as His enlightened associates. Thus all of Mucukunda’s relatives, friends and co-workers had long ago been swept away by the force of time, which of course is Krsna Himself.
Srimad Bhagavatam Canto 10, Chapter 51, Text 18
Srimad Bhagavatam Canto 10, Chapter 51, Text 20