I have been posting what are known as the O Antiphons on their appropriate days; I discussed them in more detail here. Most people are not all that familiar with the O Antiphons, but they are familiar with the classic hymn O Come, O Come Emmanuel, which was written to incorporate all the O Antiphons into a digestible hymn.
If you read the original Latin O Antiphons, you will notice there is an overarching message, beseeching God to come.
Monastic humor is seen if you look backwards at them in reverse order:
The capital letters spell ERO CRAS in an acrostic that roughly spell out in Latin: ‘Tomorrow I will come!”.
You can witness this in the original Latin form of O Come, O Come Emmanuel.