Here's a repeat of a discussion of this psalm I posted in June, 2008 (not Thanksgiving Day but any day is a day for us to be thankful.
Reading Psalm 100 and asking Who? and Where?
I once asked a group of church-goers what scripture they had memorized. Several named Psalm 100. I was not surprised because when I was a child I had been encouraged to learn this psalm either at Sunday School or Vacation Bible School.
I don't know what I made of that phrase "all the earth" when I was trying to memorize Psalm 100. I'm not even sure if I learned it in the NRSV or KJ. I'm not sure what I mean by it when I say it today. Who is being called to make this joyful noise? Am I recognizing Christians in other countries? Am I including Jews? What about Muslims? What about everybody else, those who don't descend from Abraham?
What do I think about "his gates"? Am I restricting the meaning of this phrase to church buildings (and synagogues and mosques)? Can God's gates include somewhere outside the church building? That is, am I restricting worship to a kind of formal space?