On the day I came home following lung surgery, I saw God in my front doorway. I have lived in the same 2-bedroom mission-style house for 26 years, seeing God mostly in the Passover guise of Elijah. When you're healthy, you assume God is with you all the time, and don't have to go looking.

But my cancer diagnosis changed everything, including the way I see, and what I'm looking for. As I walked up the brick steps, with a broken rib and a fresh 13-inch scar, I eyed with chagrin my weather-beaten door. Yech. I saw spiders in the eves, and ruined rain gutters. Nope, no God here.

I could change this, I thought. But how? And that's when God arrived, wearing sweet sky blue. God was not a person, but a color; not a fact, but a vibration, a Stan Getz solo made visual. If only I could bring a bit of blue into that sullen entryway, the whole place would lift. A grassy green or jade would help too, also mauve and bright terra cotta. And a lintel above the entry in deep brown, to define the welcoming space. I imagined my home as it had never been before, dressed up in Spanish tile, featuring budding flowers and wandering vines. I loved it there, and knew that love was the way I would heal. My heart burst with hope.

What right had I to hope? Cancer is an expensive disease, draining huge chunks of time and money, not to mention enthusiasm. To hire the faux artist Susan Krieg for my doorway project, I had to dig into capital that would have scared me even during my most productive years.

But God was in this place, now. I didn't care.

Avivah Zornberg, quoting Rashi, talks about the Hebrew concept of "mash-heh," the time-stopping moment that comes during a personal crisis. Like a freeze-framed film, this is the moment when a righteous person, terrified and fearing death, can change patterns and live anew.

Perhaps that's what it was for me. I am an intellectual. I believe in the rational mind, and in proof based on verifiable consequence. If painting a doorway could cure cancer, surely oncologists would require it along with updated CT and MRI scans.

But with each visit to my doctors, I face that "mash-heh" moment in a new way. There's a limit to what medicine can do, if I won't help it along. Though doctors never write out on a prescription, say, "take up gardening," or "learn piano," the bias is there. They may call it "positive thinking" or "optimism," but every one in medicine knows that health is individual. The passive patient, writes Dr. Bernie Siegel, in his now-classic "Love, Medicine and Miracles," does not help his own case. Visualize yourself as healthy, and you're halfway there.

It may be rational or intellectual to rely upon lasers and medications for a cure. It's also foolish. It misunderstands the way that, just as one mitzvah leads to another, one hope leads to the next. This clinging to life in the presence of illness is itself a miracle.

In the Passover Haggadah we read about the 10 plagues which brought the children of Israel to redemption. Nine of these are given to us gratis, as God toys with Pharaoh into letting the slaves go.

But the 10th plague is different. If the Jews are to be spared from the slaying of the first born, they must act to save themselves.

How are the Jewish homes saved? Each Israelite paints his door post and lintel with bright red blood. It is a daring act, with frightening implications: the Israelites sign up for their own salvation, electing to let God and the neighbors know that even in the darkest times, we insist upon living. The miracle they create is freedom.

Why should it be otherwise for us? Whether we're fighting cancer or for any other form of justice, we have to mean it. We paint our door posts as a sign that we're committed, we've done our part.

So the doorway is done.

Susan Krieg has painted faux tiles of vines in grassy green and jade. There is bright terra cotta. There is a lintel in deep brown. And there are mauve flowers on a field of sky blue.