Two stories, one true and one I have on very good authority:
1. Back in my former Regiment, somewhere between 40 and 50 years ago, we used to "dine in," formally, every week. Dinner always started with the PMC asking one of the two padres (we had one of each (P) and (RC) in 2RCR) to say grace. But at some recent public event both padres had been annoyingly loquacious and the colonel had made no bones about his displeasure at all the chatter. So, as we stood behind our chairs the PMC said, "Padre ... No, Captain Campbell: would
you say garce, please?" I (not really surprised at this turn of events) said: "Grace!" There were a couple of stifled chuckles and a couple of deep breathes but the colonel said, "Commendably brief," and we all got on with dinner - the padres haven taken note of the colonel's now well established views on brevity being the soul of wit.
2. My father joined
Skeena back in the 1930s. The XO was a dour Presbyterian. At the first dinner he said, "Lieutenant Campbell, would you say grace, please?" My father used the one Michael O'Leary
suggested, just above. Having said those nine words he was surprised when the XO growled: "Enough o' that papist nonsense, sir; a simple "Thank God" will suffice." So it was reported, anyway ...
Be careful with humour unless you are a well established, fairly senior officer and you know the table. Not everyone can take a joke when their god is involved.
Short is better than long.
Speak up.