Now, as I serve my country in Iraq, I see signs of that same Holy Spirit’s work in places I would not have expected. Every day, I am reminded that God is more present, powerful, and surprising than I will ever comprehend.

Present around Me. Just about every day, my team and I are driving around Baghdad, doing on-site planning for water, electricity, and sewage services. We assess needs, make proposals, and sit down with many local leaders to discuss plans and how to implement them.

It’s challenging work. Traffic is horrible, and days are long. Negotiations can be complicated and consensus hard to achieve. And, of course, we are always on guard against attacks. All of this can easily lead to hardened hearts, and yet I see so many service men and women who demonstrate compassion and kindness.

I think of an Army private, kneeling to put a new pair of shoes on a little Iraqi girl; he had asked his family back home to send them so that she wouldn’t have to run barefoot on streets covered in human waste. I think of the lieutenant who would not rest until he found a way to bring air-conditioning into the homes of some elderly people who were suffering in the intense heat. Then there are the soldiers on patrol who get to know the shopkeepers and learn a bit of Arabic; they’re sweltering in seventy pounds of gear but smiling and ready to help in any way they can.

All of this goes beyond professionalism. It shows me that the Holy Spirit is at work—even among those soldiers who don’t know the Bible or belong to any church.

Beyond My Understanding. I meet and work with many Iraqis, too. Some are Christians, and so we share an immediate bond as followers of Christ. Most, however, are Muslims. Still, despite our differences and my initial prejudices, some of these men have become good and trusted friends. It’s going to be hard to say good-bye.

One of them—a natural leader and an established family man—is among the first persons I go to when I want to help someone in special need. He never fails to respond with integrity, generosity, and deep compassion rooted in his religious beliefs.

Often, Iraqi families invite our team to leave our trucks and come share a meal. “Don’t worry,” says the household head. “You’ll be safe because you’re my guests.” Walking inside, we see the Koran displayed and wall hangings with prayers and the names of God. We sit and talk about friendship and family, politics and religion. And we eat and eat!

From our discussions, I’ve learned that Muslims revere Jesus and love Mary but don’t accept the death and resurrection of Christ for the forgiveness of sins. Even so, in a mysterious way, I have sensed the Holy Spirit at work in the Muslims I have come to know well. Each is prayerful and seeks to lead a good life in submission to God. At this point, I can only love these brothers, pray that the Spirit guide them in a way they can understand, and remind myself—again—that God’s ways far surpass my understanding.

At the Cross. These past years have made me even more aware of the Spirit’s work in me. Serving in combat zones and difficult conditions, I’ve experienced stresses and losses that have tested my faith and made me scream hatred at God. Yet in my weakness and need, I’ve discovered that the Holy Spirit is near; he is faithful, even when I fail. Sometimes his loving presence reduces me to tears of humility and joy.

My greatest challenge is being away from my wife and children. Every morning I wake up wondering, How are they doing today? When will I see them again? This separation was especially painful when we lost our third child by miscarriage. How much I wanted to return home and comfort my wife!

At times like these, my only remedy is to turn to God. Given the scarcity of Catholic chaplains, I can’t count on doing this through the sacraments. Though this, too, is very painful, I try to remember that God provides and that his Holy Spirit is always with me.

I keep a visual reminder of this reality on the desk in my bedroom. It’s a polished iron crucifix on a stand—I got it at a nearby souvenir shop in exchange for a guitar I’d received. That crucifix brings focus not just to my room but to my life. Sitting before it, I offer my duties as a prayer of love and submission to God’s will. I bring him my fears and hopes—for my family, my team, my friends, myself. I thank him for his mercy.

Scripture says that “the love of God has been poured out into our hearts through the Holy Spirit that has been given to us” (Romans 5:6). Each time I make my simple offering, I learn again that this is true.

US Army Captain Sean O’Brien received the Purple Heart for service in Afghanistan, where he sustained injuries while leading a humanitarian assistance and support mission. He now facilitates similar projects in Iraq. Sean and his wife, Dawn, and their two young children are from Sanborn, Iowa.