Why was Adam's relationship with God broken when he sinned?
Adam's relationship with God was broken because the spirit in him died the moment he sinned. His spirit was the core of his being where he fellowshiped and had communion with God; when that spirit died, the fellowship was severed. At that same instant, his mind, will, and emotions became a sin nature.
Les explains that Adam's spirit was the part of him where he fellowshiped and had communion with God. He distinguishes the soul—the mind, will, and emotion, which he calls the personality—from the spirit, the core of our being wherein Adam had fellowship with God and wherein believers have it restored. The moment Adam sinned and showed disobedience, his mind, will, and emotion immediately became a sin nature. At the same instant, his spirit-and-God relationship was broken, because the spirit in Adam died. That death severed the fellowship. Les also notes Hebrews 4:12, which says the Word of God can divide soul and spirit, showing they are distinct even though closely intertwined.