Be the great God between your shouldersIt's by the Rev. Carol Ford, of the Kirk of Scotland, inspired by Deuteronomy 33:12, or so says the Vatican website.
To protect you in your going and coming;
Be the Son of Mary near your heart;
And be the perfect Spirit upon you pouring.
In writing, we can see that this is the subjunctive mood ("be that as it may"). However, we are reliably informed that some listeners took it for an imperative ("be thou my vision," or "be gone"). Were it the latter, it would indeed have been ill-advised.
Which is just one more reason that grammar matters.