Why so many of them are slow? It bothered me, but now, I'm good with it and here's why:
I think it's like when you're on a roller coaster; they say the people who are truly scared are totally silent. Or when you witness a huge fire or a big accident, or a major storm - you don't scream about it, you're silent - taking it all in. And, when you give birth (or witness it) - you don't scream and yell in excitement in the delivery room - even though it is VERY exciting - you are still, you are in awe, or you just cry and can't talk, like I did - you "ponder these things in your heart" as Mary did (Luke 2:19)
With a little help from Websters, and my Ipod, I was able to see the connection.
"Come and behold Him" = to look, to see, to regard
"Oh come let us adore Him" = worship, love greatly, honor highly
When we are doing these things; it is a deep, internal regard - something we do with our hearts - something that shows what we esteem. I scream excitedly when my child scores a goal, but I am silent and in awe, when she is born. Because that is bigger.
This is the biggest thing that had ever happened - God has come to earth - as a baby - "Fall on you knees" (O, Holy Night), "(shepherds) quake at the site" (Silent Night)! Be silent and treasure these things with a nice, slow Christmas Carol...