How to adherents to Christian mortalism understand death and the human soul?

This is a question for those who see Christian anthropology of one part (Monism). The belief that human soul is not immortal and that man is a *unity*, that is, not a *duality* of *soul-body*, or a *trichotomy* of *spirit-soul-body*, but holistic, one part. The first part of my question is, how do you understand – in light of man not being dualistic and such – references to *soul* and *spirit* in the Bible, in general (e.g. 1 Thessalonians 5:23, NIV)? > May God himself, the God of peace, sanctify you through and through. > May your whole spirit, soul and body be kept blameless at the coming > of our Lord Jesus Christ. What is a soul? What is a spirit? And finally, if humans beings are completely dead after death, how are references to "sleep" (i.e. death) understood in the Bible? For example, 1 Thessalonians 4:14 (NIV): > For we believe that Jesus died and rose again, and so we believe that > God will bring with Jesus those who have fallen asleep in him If the person is dead, how can we talk about him as sleeping? Or consider Psalm 16:10 (NIV): > because you will not abandon me to the realm of the dead, nor will you > let your faithful one see decay. Same question applies, how can a dead person be abandoned in a realm? I understand this is to be taken metaphorically somehow. But, in essence, if a person ceases to exist.