A career as an oncologist has taught me an important truth about why the Christian holiday of Easter matters so much: It’s not just pain, but suffering, that makes us fully human.

For many years, I didn’t differentiate between the two. They are so often coupled as part of a blithe rhetorical pair (“pain and suffering”) that they seem very nearly the beginning and ending of a single word.

In fact, their meanings differ in ways that I, as a doctor, know too well.

Pain resides in the physical body, mediated by nerve endings and conveyed along axons and neurons to the brain. Pain urges the body to escape whatever is causing that sensation.

But suffering means something more.

Suffering is, in effect, the psychological, emotional, spiritual and even existential effects of our pain on our sense of self, the universe and the former’s place in the latter.

Thus, at least strictly speaking, while pain must be mediated by physical nerve fibers, suffering requires none. When a loved one dies, their passing may involve deep physical pain, but their death may leave the bereaved with suffering just as great, even if nary a nerve fiber was involved. Similarly, when cancer robs patients of this body part or that ability, an involved surgery may initially cause pain, but the resulting effects may linger as suffering that lasts much longer.

Similarly, even beyond its resultant physical agony, cancer gives rise to deep existential questions about God, love, fate, justice and the meaning of the universe. What, after all, are we to make of a natural order that births both the beauty of Yosemite Valley and the agony erupting from a body ravaged by cancer?

Of course, every life differs — and some suffer more than others — but most of us will eventually fall victim not just to pain, but also to the wintry certainty of suffering.

And that is why Christians find special meaning in Easter.

The great scandal of Christianity is to invert traditional power hierarchies and upset comfortable expectations. In Jesus, and most especially in the events of Holy Week, Christians find a God who is defined not by power, but by vulnerability. Jesus wins love and loyalty not because he was obviously mighty, but precisely because, by any traditional metric, he was not.

What almost dying taught me about hope and joy

In the scenes that unfolded in Gethsemane and on Calvary, Christians worship a God who occupied a body subject not just to physical pain, but also to existential suffering. In this vein, Jesus’ haunting plea to his Father — “why hast thou forsaken me?” — rings with special pathos. We sense, as scripture teaches, that Jesus “took upon him (our) infirmities, that he (might) know according to the flesh how to succor his people in their infirmities.”

He wins our affection by carrying our afflictions.

That he suffered “according to the flesh” suggests Jesus came to embody and understand the gritty reality of being human in all its fleshy particularity.

Thus, Jesus’ own suffering grants him the empathy that allows him to speak comfort to us in our moments of deepest darkness. God can succor us because he became one of us. And in this, Easter offers us both comfort and a call. Comfort because God became mortal — willingly bearing “the slings and arrows of outrageous fortune” — to understand just how we feel. And with that knowledge, we recognize that his empathy shines infinite and perfect.

His call comes as this reminder: It is only by willingly entering into the suffering of others, by inhabiting the deepest sadness of our erstwhile enemies, that we truly follow Jesus. If we are to enter “the fellowship of his suffering,” it will be by willingly bearing the burdens of those we see suffering around us. Easter is not just a promise of succor for us — but a reminder that to follow Jesus is to offer that succor to the disconsolate, wherever they may be found.

Dr. Tyler Johnson is co-host of the podcast “The Doctor’s Art,” a clinical assistant professor of oncology at Stanford School of Medicine and a director of the Stanford Oncology Fellowship Program.