Man is a living soul. Gen clearly states that man became a living soul when given our life's breath from God.. it is not stated that an eternal soul entered man's fleshy vessel for a temporary visit. Our spirit is what makes each person the individual that they are,, we sometimes call it the mind. A man/soul is not destroyed, and it does not completely cease to exists upon our physical death, this one is of the flesh. The Bible often refers to death as sleep, and it is common knowledge among people of the Bible. Even Jesus slept in the grave for 3 days and 3 nights before He rose. His body was severely injured, obviously, and His flesh would have started to decompose, but these things were restored and perfected at the time of resurrection. He was the first. The Bible clearly states that when Jesus returns, the dead in Him (true Christians, the true saints) will rise first. (Why rise and wake if you are already hanging out in heaven?) They will wake up, and rise. Then those (true Christians and saints) who are alive at that time will be instantly changed. So people who are alive with serious physical problems will be changed at that moment, become like Jesus, and rise to meet Him.. along with the dead who have been cremated/decomposed.. when they wake they will be like Him and rise. It is unclear and unstated what exactly this glorified existence will be like, but it is stated in the Bible that we will be known as we are now, and that there will be memories of individuals, so our earthly (fleshy) form of existence has to be relevant in some way. The theory of dying, and then our separated immortal soul floats off, going immediately to heaven or hell just doesn't match anything that the Bible teaches us about death, and what God has planned out for eternal life.
Tons of verses here to support these things in the Bible. I'm sure most are known, but I would be happy to retrieve them for any specific point if anyone would like them.
mik