Adam and Eve transgressed
On the sixth day "God created man in His own image" (Ge 1:27) in "spirit and soul and body" (1Th 5:23). "It is I who made the earth and created man upon it" (Isa 45:12). "It was Adam who was first created" (1Ti 2:13) and in Hebrew his name means "humanity." In an extended sense the word "flesh" is also humanity. The human race inherits from Adam for, "as in Adam all" (1Co 15:22), applies to everyone. "God saw all that He had made, and behold, it was very good" (Ge 1:31). Therefore it cannot be concluded that man is inherently sinful.
When God put Adam in the Garden of Eden he "commanded the man" (Ge 2:16) "from the tree of the knowledge of good and evil you shall not eat, for in the day that you eat from it you will surely die" (:17). It was not said that "you will drop dead" as if it was poisonous. So to die must mean that death was not part of God's scheme of things, but it would transpire if Adam was disobedient. Later it happened that "every intent of the thoughts of . . . [man's] heart was only evil continually" (6:5). So God "was sorry that He had made man on the earth" (:6).