I have always believed in the power of prayer. At times that faith has been tested, questioned and even doubted. However, events in my life have proven beyond a shadow of a doubt in the power of prayer.

One such experience occurred during my years in the military. I was a Navy hospital corpsman assigned to the Fleet Marine Force in Camp Lejeune, North Carolina. Subsequently, my orders to join Marine Amphibious Unit 22 came through and we were tasked to relieve Marine Amphibious Unit 24 in Beirut, Lebanon, serving as part of a multinational peacekeeping force.

While en route to Beirut, we learned that MAU 24 had been the target of a terrorist attack when a truck bomb killed more than 300 Marines and sailors on Oct. 23, 1983. The reality of our situation began to creep in: We were not going to find a benign role like keeping the peace — we were going to be active combatants in a civil war.

We landed in Beirut in late 1983; it didn’t take long for the daily routine of military life to take over. We settled into our medical tasks like sick calls and receiving casualties, and then our routine would be interrupted by a radio call, “All hands to assigned bunkers at this time.” Each bunker had a corpsman assigned and each held about six to eight people. Once the call came in I would grab my helmet, flak jacket and medical bag, and head for my bunker. These bunker calls happened almost every day and led me to describe life in combat as 99% boredom and 1% terror.

It was in that 1% that I found the power of prayer, in a place I never expected: those bunkers. We all knew the sandbags and earth surrounding us could not protect us from the direct impact of a mortar shell. Everyone in that bunker could feel death tugging at his sleeve, and it got very quiet. I put my head down and hands together and prayed in silence, as mortar shells exploded around us. It was easy to imagine others were praying as well. We all prayed for the same thing: another day, or another chance to redeem ourselves, or maybe a promise of a lifetime of faith for getting us through this trial.

Once the shelling stopped, our relief from having survived was mixed with the sad realization that in return for our bunker not getting hit, another bunker usually did. We would return to our duties, Marines to their posts, and corpsmen would be needed in the battalion aid station to care for incoming casualties.

It really should not be a big surprise to find Marines praying. After all, the motto of the Marine Corps is Semper Fidelis — “Always Faithful.” Faithful to what, you might ask? Perhaps to the Marine Corps, to their brothers and sisters in arms, to family — and yes, to God. It is said that a Marine who is wounded in combat calls out for his God, his mother and his corpsman. As a corpsman, I always thought that was some pretty good company to keep.

Due to the constant stress of mortar attacks, rocket-propelled grenades and sniper fire, we quickly adopted a mindset of “no worries.” You had no control over the situation surrounding you — worrying about it made no sense and only added to the stress. We left our fate to a “higher power.” For me, it was a sense of great ease and calmness once I gave up worrying about my own mortality and found hope in my prayers to God that he would always be at my side every moment.

Even now, as I reflect on those days in the bunkers, I remember another incident that showed me the power of prayer. While on the deployment in Lebanon, a group of us got two weeks of liberty (leave) in Israel. We went to the port city of Haifa and got a tour bus which took us to Tel Aviv, Bethlehem, Capernaum and finally to Jerusalem. We made a stop at the “Wailing Wall.” It is so named because it was the only remaining wall of the Jewish Temple destroyed centuries ago. Each day devout Jews go to the wall to decry its destruction and pray for the restoration of their Temple. This is the power of persistent prayer.

Certainly, Psalm 23 (“The Lord is my shepherd … though I walk through the valley of the shadow of death, I will fear no evil”) has comforted many people for many years. Most take the “shadow of death” as a metaphor for some ailment or challenge in their life. But for anyone who walks that fine line between life and death, it takes a more literal meaning. The passage comforted me by assuring my God was at my side in those bunkers responding to my prayers — the same way God responds to all our prayers no matter where we say them.

God will never tire of hearing our prayers, so you should never get tired of saying them — even if you are not in a bunker.

Richard D. Bigelow served as a U.S. Navy hospital corpsman from 1980 to 2004, including deployments to Grenada, Beirut and Iraq. He writes from Orlando, Florida.