What Is a Prayer?
When one goes to pray to the Creator to help him, he must first prepare and examine himself, to see what he has and what he is missing, and then he can know for what to ask the Creator’s help. This is the meaning of the words, “Out of the depths I have called upon You, O Lord.” “Depth” means that a person is in the lowest possible state, as it is written, “Depths of the nether-world,” meaning his deficiency is below and he feels that he is beneath all other people.
In other words, he feels so remote from Kedusha (holiness), more than all other people, meaning that no one feels the truth, that his body has no connection to Kedusha. Hence, those people who do not see the truth—that they are remote from Kedusha—can be satisfied with their work in the holy work. But he is suffering from the state he is in.
– Rabash, The Rungs of the Ladder, “What is, ‘A Woman Who Inseminates First, Gives Birth to a Male,’ in the Work”