What Christmas song has the initial wacib?

The Christmas song that has the initials WACIB is "We Wish You a Merry Christmas." Here are the full lyrics to the song:

We Wish You a Merry Christmas

> We wish you a Merry Christmas,

We wish you a Merry Christmas,

We wish you a Merry Christmas,

And a Happy New Year!

> Good tidings to you,

And a Happy New Year!

Good tidings to you,

And a Happy New Year!

> We won't go until we get some,

We won't go until we get some,

We won't go until we get some,

So bring it right here!

> We wish you a Merry Christmas,

We wish you a Merry Christmas,

We wish you a Merry Christmas,

And a Happy New Year!