I have spent the majority of my life studying the Bible. Through personal reading as well as formal university studies, I have learned much about things such as the nature of God and how to live as a Christian.

As a Salvation Army officer with 34 years of service, I have preached on Bible passages that teach about the faithfulness of God—the faithfulness that sustained the Israelites in the desert for 40 years. The Bible declares the trustworthiness of God by the accounts and testimonies of biblical writers—the deliverance of the Israelites from Egypt (see Exodus 1-14), the falling walls of Jericho (see Joshua 6) and the crossing of the Jordan River (see Joshua 3).

But it's one thing to know the Bible and to read the theory of a faithful God; it's quite a different thing to know God and translate that theory into practice, especially when life presents us with serious challenges. Can we really trust the promises of God when life does not go the way we wish? In some of the most desperate circumstances of our lives, where is God? Why do things happen the way they do, especially when we spend our lives serving him?

A Promise Made
There have been a number of times in my life when difficulties have tested my own certainty of God's faithfulness, but none more than over the last six years. Since 2011, I have been battling serious stage 4 cancer (initially diagnosed as stage 3).

When I was first diagnosed that October, I remember leaving the doctor's office and sitting in my car. The first thoughts that came to me were words from Psalm 139:16: “All the days ordained for me were written in your book before one of them came to be.”

I promised myself then, without knowing what would lie ahead, that nothing was going to happen to me that was not subject to the absolute sovereignty of God.

Life Sentence
I commenced chemotherapy and radiation immediately following the diagnosis. After 28 radiation treatments and almost three months of chemotherapy, I was prepared for my first major surgery. This was an extremely traumatic experience, leaving me hospitalized for days and in recovery for weeks.

A further round of chemotherapy began, as did a roller-coaster of emotions. The surgeon and oncologist were convinced that they had conquered the disease even though four of the six lymph nodes taken during the surgery were cancerous. They were so certain that the chemo port surgically inserted to receive chemotherapy was removed. Why keep some foreign object in my body that would not be needed again?

Their words encouraged me but it wasn't long before the roller-coaster started again. A scan revealed that the cancer had spread to my liver, and a biopsy confirmed it. The liver surgeon was certain that he could remove the tumors. Plans were made for surgery and another round of chemotherapy followed, which required a new port to be surgically inserted to receive the chemo.

Was it possible that this could be the end of this disease? Could the surgery and further treatment be the means to a cure?

Not long after that, the cancer spread again and the difficult journey continued.

In March 2014, following another surgery, tests revealed that the cancer had spread to other organs and locations in my body, and it was no longer curable. When asked about life expectancy, the oncologist estimated six months without chemo and two years with it.

Hope Defined
Since the 2011 diagnosis, there have been five major surgeries, 28 radiation treatments, approximately 150 chemotherapy treatments with numerous chemo drugs and hospitalization for chemo complications.

What does this say about the faithfulness of God? These have been extremely challenging times. My body has often been reduced to sheer physical and emotional exhaustion. I have experienced some of my most wearying days, but I also recognize that God has performed miracle after miracle in my life.

Three years have come and gone since March 2014, and the battle continues. I've recovered from surgeries that threatened to impact my health and tolerated treatment after treatment of chemotherapy.

At the same time, my relationship with God has been strengthened by the realization that there is nothing that can happen to me of which God is not aware and which he cannot use for his purposes.

God is at work and it is not how he works that matters, it is who is at work. It is not how we are healed but who is healing. Therefore, I place each day in his hands.

I am completely aware that healing for me may happen when life on this earth is complete and I stand in the presence of my heavenly Father. But, as a Christian, isn't this the future for which we strive?

As I continue to battle, God has proved his faithfulness. He has been so real over the past months and years. He has given me a peace that I would never have thought possible. He has given me joy in the midst of difficulties. He has given me grace and courage to stand up to the challenges of suffering. These days, I am totally God-reliant and I have proven his faithfulness day after day.

Does that mean that there have been no struggles? Absolutely not! The months and years since October 2011 have not been anxiety-free. I hardly need to say that life has been difficult.

I hate this disease. I hate what it does to the people I love. I have struggled, I have been discouraged, but I have never ceased to be amazed at God's faithfulness. God teaches me not to live my life defined by disappointments. Rather, he helps me to live life defined by what he has done and will continue to do, for me and in me.

I serve a God who is bigger than cancer. I fellowship with friends whose prayers are more powerful than cancer. Cancer may possibly kill this body, but it has not and will not kill my spirit. I have a hope that goes far beyond this earthly body … and it is glorious!

Lt-Colonel Joan Canning is the assistant chief secretary of the Canada and Bermuda Territory.