The Blood That Is No Longer Your Own

In a bone marrow transplant, something happens that sounds more like scripture than science. After a patient's diseased marrow is destroyed through chemotherapy, a donor's healthy marrow is infused into their bloodstream. Over the following weeks, those transplanted stem cells find their way into the hollows of the patient's bones and begin producing entirely new blood. The recipient's blood type can actually change to match the donor's. When doctors test the blood cells afterward, they carry the donor's DNA, not the patient's. The medical term for this is chimerism — two genetic identities existing in one body, with the new life gradually overtaking the old.

The apostle Paul could have been describing this very process when he wrote, "I have been crucified with Christ and I no longer live, but Christ lives in me" (Galatians 2:20). The old, diseased life — poisoned by sin, producing death — is put to death. And then something foreign, something wholly other, is introduced. The life of Christ begins flowing through us, producing what our old nature never could: love, patience, gentleness, peace.

No one who receives a bone marrow transplant pretends they healed themselves. They were dying. Someone else's life was poured into them. That is grace. And just as the donor's marrow keeps producing new blood every single day, the Spirit of the living God keeps renewing us — not once, but continuously, until the transformation is complete.