As Catholics… we believe that original sin isn’t something committed, it’s something contracted. We recognize that we have received from Adam and Eve a human nature devoid of the divine nature God originally entrusted to them. As such, we don’t so much see original sin as a “thing,” as we do a lack of a “thing” — that “thing” being sanctifying grace. And sanctifying grace isn’t just religious rhetoric for something special. It is the Holy Trinity dwelling within the soul.
What that means for us is that we receive a human nature from the moment of our conception. But because we receive a human nature without a divine nature, we’re spiritually dead from the start. That’s our inheritance from our first parents: spiritual death. We’re physically alive but spiritually dead because God’s life does not dwell in us.
Baptism changes that.
Sometimes we talk about Baptism as “wiping away the stain of original sin.” But that’s a flawed metaphor. It inadvertently suggests that something is there before Baptism that isn’t there afterward — almost as if we could perform a spiritual x-ray of our soul, before and after Baptism, showing first a dirty soul, which is later made shiny and new. But again, it’s not the presence of something before Baptism that’s the problem. It’s the absence, the absence of divine life.
That divine life is what baptism restores. It gives us back the divine life that Adam and Eve lost.