Exodus 3:5 & 6
"'Do not come any closer,' God said. 'Take off your sandals, for the place where you are standing is holy ground.' Then he said, 'I am the God of your father, the God of Abraham, the God of Isaac and the God of Jacob.' At this, Moses hid his face, because he was afraid to look at God." NIV translation
We are introduced to the principle of "holy ground" and so we must define it. As we see here, there was nothing special about the dirt itself but it was set aside (holy) for the purpose of Moses' meeting with God. With that in mind, we should understand that everywhere that we study God's word, pray, sing, dance, etc. in worship is holy ground. There are many even today that think we must go to a specific building to meet with the Lord but He is not interested in the building but in our coming to Him.