The grace goes:
Some hae meat an canna eat,
And some wad eat that want it;
But we hae meat, and we can eat,
And sae the Lord be thankit.

The modern English translation is:
Some have meat but cannot eat,
Some have none that want it;
But we have meat and we can eat,
So let the Lord be thanked.

What is the Selkirk Grace?
The Selkirk Grace is a Scots-language prayer traditionally recited at a Burns supper. Usually, the host will say a few words to welcome their guests to the dinner, stating the reason for the gathering.
, when all the guests are seated, just before the haggis comes out, the Selkirk Grace is recited. It’s a short prayer, originally said in the Lallans dialect of lowland Scotland, which gives thanks to God for the meal about to be eaten.The Selkirk Grace isn’t just reserved for Burns Night and is still used at many social gatherings in Scotland, such as weddings, birthdays, and at Christmas.

Where does the tradition come from?
A common myth about the Selkirk Grace is that Robert Burns himself wrote it. In fact, the grace was already known in the 17th century as the “Covenanters’ Grace” or “Galloway Grace”. The prayer became attributed to Robert Burns after he recited it at a dinner party held by the Earl of Selkirk in 1794, which is where its current name comes from.