2 Samuel 7:18 KJV
Then went king David in, and sat before the LORD, and he said, Who am I, O Lord GOD? and what is my house, that thou hast brought me hitherto?
Concerning the fact that David "sat before the Lord," Poole comments
"....that he did not barely present himself before God but abode there for some competent time, that he might with God’s leave pour out his soul freely before him."
And Barnes says
"... Modern commentators mostly take the word here in the sense of waiting, abiding, not sitting: but sat is the natural rendering. David sat down to meditate, and then rose up to pray."
A case may be made for the use of sitting as a posture of worship before the Lord, but more importantly than the body posture is the issue of abiding. I like Poole's standard of "some competent time." One just does not meet God in a hurry. It is not God's way, and it is certainly not an appropriate spirit in man that would approach God as something to do in a hurry. God deserves and in fact, requires "some competent time" be spent with Him.
This is much if not most of the problem with contemporary Christianity. We are busy about our workings; so busy working for God that we don't have time for God Himself.
So sit down!
Slow yourself for a bit. Stop. Meditate, muse, and listen.