It was not long after Adam was told not to eat of the forbidden tree, that he ceased to like God. God is holy (Ps. 99:9), and when Adam sinned, he not only ceased to be holy, he ceased to be alive spiritually. God had told him that the day he ate of the forbidden tree, he would die. When we look at the life of Adam, we find he lived several days after he ate; in fact, he lived to be 930 years old (Gen. 5:5)! Was God wrong? No! The day, in fact the instant he disobeyed God, he died spiritually.
Paul wrote, "Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned" (Rom. 5:12). Like Adam after he sinned, unsaved man is alive physically, but he is dead spiritually (Eph. 2:1, 5). That is why we need to be born again of the Spirit of God! Those who have been born again, have been born again spiritually by the work of the Holy Spirit (Jn. 3:3-8). Because born again believers have been made alive spiritually, Paul could describe us as being, once again, a triune being like God (1 Thes. 5:23).
The truly sad thing is, the vast majority of mankind is not aware that they are dead! They have no idea that there is more to life than the physical. Oh sure, nearly all individuals believe in some form of god, and they believe that if they do certain things, and avoid doing other things, they might appease their version of god. In fact, that is the very definition of religion. But what they miss is the fact that they are spiritually dead, and that they, in and of themselves, cannot change that. Only God can provide the new birth necessary for man to be, once again, like his Creator!
All the works in the world cannot make a dead man live; only God can!