Helena,
You took the words right of my mouth! I'd almost finished a reply, left it whilst I was eating, came back, did a preview, and there yours was! As you'll see, I mention both Ps 51 and the Bible in general.
Moe,
John 4:24 is one of my favourite verses. I'd agree that consistency is important - it also seems to be what Ps 51:6a (another one of my favourites) is suggesting.
However, we are all imperfect, and hence will not be 100% consistent. But this doesn't disqualify us from worshipping provided that we acknowledge our failures, bring them before God, and are willing to let Him transform us on a daily basis.
If you look at John 4:23, the preceding verse, it says that the Father
seeks worshippers in spirit and truth. So it suggests that this is something we should be aiming for, but are probably not there yet (well, I'm not, I don't know about everyone else...).
EDIT: I've deleted a line here that would have left you scratching your heads thinking what is he on about. I had a comment at the start about baseball that I deleted before posting this reply, but I forgot to remove this reference to it. It was of no relevance to the discussion.
I can think of three other interpretations of "..and in truth"
(1) The truth about God. Our worship will reflect who we think God is. Pretend you are an alien who's walked into a church service!! What impression of God would you get? Of course, we won't know the full truth about God before we get to heaven, but in many cases our understanding is quite flawed and needs much study. We all have plenty to learn. I'm also reminded of the point about childhood experiences in Dean's report of the Tom Kraeuter seminar - check it out <URL url="http://zionfirefriends.com/index.php?showtopic=467">
here.
(2) The truth of the Bible. The principles of our worship should be the same as those found in the Bible. One thing I've noticed is that biblical worship varies considerably - from wild celebration to everyone flat on their faces in silence. And it happens in different times and places. So perhaps our worship should also reflect this diversity. And, of course, we should be seeking to live in accordance with the truth of the Bible.
(3) The truth of who we are. Again, there's a lot of diversity here. God has made me a dancer and that's an integral part of my worship. I don't expect everyone else to dance, but neither do I expect them to say "dancing isn't my thing so we shouldn't do it". There's also the truth that we have to come as we are (as we can't be anything else) and not put on a false face for God. Think of the story about the pharisee and the tax collector.
I don't regard these three interpretations, and Darlene's, as being mutually exclusive. There's so much meaning in this verse I think they all have validity.
Blessings,
Dave
PS Sorry, I haven't time to write anything about the "in spirit" bit.