United States, and I served in the Army as an Airborne Ranger. I was in for 11 years, and retired as a Staff Sergeant (E-6) due to medical reasons.
I served in combat in two places, El Salvador in 1985, and the Persian Gulf in 1991. In central America, I was a sniper supporting the Salvadorans in fighting the FSLN. My time there was short, consisting of several 4-day missions into the mountains to interdict infiltration routes. Getting shot at was very scary, but my training got me through. In the Gulf, I was a squad leader in the 101st Airborne’s recon company. The actual combat time was brief, consisting of a jump into what would become Cobra to scout out the site for the air assault, then being part of the movement to the Euphrates river and highway 8 to serve as a blocking force. In that role, we did engage in heavy exchanges of fire with retreating Iraqi forces, and several of our people were wounded. Once again, it was quite frightening, but training and endless drills had sharpened us to the point where we did our jobs.
Religion only really came into my military career three times. The first two happened early in OSUT (One Station Unit Training, what they call Basic Training for the infantry.) Our first Sunday, we all had to attend church, not for really religious reasons, but so we could get a short block of instruction on the services provided by the Chaplain.
The second came about five days later, when we got out dog tags. The last line on a set of tags is religion. Mine, for example, read NO REL PREF. We all sat in a semi-circle around Drill Sergeant Colom, and went down the lines, checking for errors. Last name, first name and middle initial, service number, blood type, and finally, religion. As always in the Army, mistakes were made.. names spelled wrong and the like. But when we got to religion, all hell broke loose. A kid from Alabama raised his hand and said that they had him down as one type of Christian, and he wasn’t one of “those arm-waving, singing frauds.” To which the three people who belonged to that sect immediately forgot that we were in the Army, and within ten feet of a Drill, and jumped to their feet to defend their faith. Amazing. In three seconds these people forgot everything they had learned.
The last came while serving in the 3/7th Infantry. I was forced to room with a really hardcore fundamentalist. This loser refused to believe that anyone was allowed to have fun. We ignored him.
When in the field, and taking fire, I never thought about any sort of deity, I thought things like “Where the fuck is our air support?” and “I am going to turn these assholes into paste.”