The reality of sin and evil are self-evident. Not so self-evident is the origin of these things. Where does evil come from and whom can we blame for it? These are age-old questions to which the Bible gives definite answers.
Our Original State
The Bible says humanity was created good and in God’s image (Gen. 1:27,31). Being created “good” means that Adam and Eve were created exactly the way God intended them to be. They were created in such a way that they could choose not to sin. They had free will. They were created able to freely make choices – choices for which they would be responsible. Being created “in God’s image” means they reflected God in some ways – for example, in their capacity to love or to communicate, but also in “true righteousness and holiness” (Eph. 4:24).
The Fall into Sin
Adam and Eve were tempted by Satan and they freely and willingly gave into that temptation. There was no outside compulsion. They rebelled against God and ate the fruit from the tree of the knowledge of good and evil (Gen. 3:1-7). They made an evil choice against God’s will and this was a choice for which they would bear the full responsibility.
Our Fallen State
After Adam and Eve misused their free will, corruption has spread to the entire human race (Gen. 6:5). We are all fallen. Consequently, the image of God in humanity has, at best, been vandalized. Moreover, in our fallen, unregenerated condition, we are not able not to sin. Unregenerated human beings still have a free will, but they can only use it in a sinful way (Jer. 13:23). As free will is exercised in that fallen human nature, there continues to be full personal moral responsibility (Acts 3:14-15).
Adam was the representative of all humanity in the Garden of Eden. When Adam fell, it had consequences for the entire human race. Every single human being born since then (except Jesus!) has been born with what we call original sin. This means two things:
Adam’s guilt is accounted to each one of us (Rom.5:18). Because he was our covenant head, we bear his guilt as his descendants.
Adam’s pollution is transmitted to each one of us (Jer. 17:9, Rom. 7:18). We are all born with an inclination to sin. We don’t have to be taught how to sin. We know how to do it naturally.
We distinguish original sin from the actual sin we commit daily.
Praise God that through the gospel of our Lord Jesus we are delivered from our original sin, as well as our actual sins! The gospel restores us into people who want to and who actually do honour God with their lives, just as Adam and Eve were designed to do.
 Historically, Reformed theology has distinguished between the image of God in the broader sense and the narrower sense. In the narrower sense of “true righteousness and holiness,” we confess that the image of God has been obliterated by the fall into sin.