SB 3.29.3

In this verse, the word samsrtiḥ is very important (s-a-m-s-r-i-t-i-h). Samsrtiḥ means continued journey on the path of birth and death. And against this word there is another word which is called sreyaḥ-srtiḥ (s-r-e-y-a-h s-r-i-t-i-h). Sreyaḥ-srtiḥ means the prosperous path of advancements towards the Supreme Personality of Godhead, and samsrtiḥ means a continued journey towards the darkest region of material existence. So people without knowing, without any knowledge of this material world and God and himself and their eternal relationship are actually, in the name of progress in material advancement of civilization, they are going to the darkest region of material existence. The darkest region of material existence means to enter into the cycle of different species of life other than human being. The ignorant men, they do not know that after this life one is completely under the grip of material nature and will be offered a life which may not very congenial.

The purport continues. How a living entity gets different kinds of bodies will be explained in the next chapter. But we should know that this continued change of different bodies and birth and death is called samsrtiḥ, and the request of Devahūti to his [her] glorious son, Kapila Muni, to explain about this continued journey is to impress upon the conditioned soul how they are undergoing a path of degradation without understanding the path of bhakti-yoga or devotional service.