Q. I was reading and came across this verse in Genesis 5:3. And Adam lived an hundred and thirty years, and begat [a son] in his own likeness, after his image; and called his name Seth. Why is this worded like this?
A. Genesis 1:26-27 tells us God created Adam and Eve in His own image and likeness. When Adam and Eve sinned, a change came over them. We know this because they suddenly realized they were naked and hastened to make clothing to cover themselves (Genesis 3:7). This change resulted in a genetic flaw we call the sin nature today, and meant that all their descendants would have a propensity for sin that makes them unable to please God, apart from faith (Hebrews 11:6).
Saying that Adam “begat a son in his own likeness and after his image” means Seth didn’t just resemble Adam, he was also born with a sin nature that he inherited from his father. The same is true of all humans. We all resemble Adam and we have all inherited a sin nature. That’s why we need a Savior.
Romans 8:28-29 says God’s will is for us to be conformed to the likeness of the Lord Jesus. By believing in Him, we are justified by His blood, and at the resurrection / rapture we will be divested of the sin nature we inherited from Adam.