Adam and Eve were not supposed to die. God originally blessed them in such a way that they would not even suffer, get sick or grow old. Paragraph 376 of the Catechism of the Catholic Church attests, "As long as he remained in the divine intimacy, man would not have to suffer or die."
God had originally intended for the first parents and their progeny to live full lives, grow in virtue and finally enter Heaven without ever having to suffer. They did sin, of course, and thus lost this blessing not only for themselves but for the entire human race as Romans 5:12 relates, "so death passed upon all men."
Along with immortality, Adam and Eve were additionally given two other gifts that were called preternatural or beyond nature. The first was the gift of knowledge called infused science. This was like a mental owner's manual of life that God download into their minds. They thus knew how to live and how to teach the human race about life.
An example of this knowledge is found in Genesis 2:19 where Adam names the animals, which shows he first understood them. Their minds were also made nimble and prone to learning.
The third preternatural blessing, called the gift of integrity, allowed their emotions to be balanced and reasonable. Paragraph 376 of the Catechism says this gift afforded our first parents an "inner harmony" that promoted an external "harmony between the first couple and all creation."
God had even blessed nature making it conformable to their service. This was shown in Genesis 2:15 where God placed them "into the paradise of pleasure to dress it and to keep it." After they fell from grace, this blessing would be withdrawn and the earth would then yield "thorns and thistles."
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