This is a good one for a sub-editor to write about because the first thing to establish is where the comma goes in the first line. It is not where Dickens places it. In the 16th and 17th centuries, the period from which the carol is thought to date, the word ‘rest’ was a verb meaning ‘keep’ or ‘allow to continue’, and ‘merry’ had a wider sense of ‘contented’, ‘bountiful’ or ‘prosperous’.
Thus the first two lines could be paraphrased as: ‘May God allow you to remain contented, gentlemen/Let nothing dismay you’.
For this reason the often-used variation of ‘ye’ for ‘you’, presumably to make it sound authentically archaic, is incorrect. ‘Ye’ is for addressing someone directly, as in ‘Oh ye of little faith’. In the context here, the gentlemen are the object of the appeal to God and ‘you’ is grammatically correct.
https://www.conservativewoman.co.uk/hea ... gentlemen/
