Night, being a time of day, cannot actually kneel, thereby becoming personification. Tracy K. Smith uses this personification to show the utmost power that this spiritual "you" now has. Earlier in the poem she describes a loneliness, a "solitary country". However, as time goes on, this mythical "you" gains power and soaks up light as it has "nothing to fear". The "you" in this situation, no longer has anything to fear. Generally, night is a time in which people are afraid, as people are afraid of what could be hiding in the darkness. However, once in heaven, Tracy K. Smith is trying to say that there is no more fear, and that the host of fear bows before you. This correlates with the "reconstruction" phase.