What is the origin of hands lifting in worship? You don't need to go far to agree that raising hands while singing and worshiping (with music or prayer) is a big Christian tradition.

I've always thought that this was some reference to Psalm 134.2:


  Lift up your hands in the sanctuary, and bless the LORD. (KJV)


Or to 1 Timothy 2:8:


  I will therefore that men pray every where, lifting up holy hands, without wrath and doubting. (KJV)


So, I can imagine some biblical basis for it. But my question is: When this started on church's history? Is there some theology behind it? Any Father who registered, did or encouraged it? Or is this a thing of modern christian movements?
It goes all the way back to Genesis 29:35 at least with Leah raising her hands in praise to YHWH in naming Judah. As a Biblical Hebrew professor thinking in Hebrew, I find the Old Testament full of hand raising. After the most frequent verb for spoken praise HaLeL (Strong's #1984 &amp; 8416), the word most translated (53 times) as "praise" is the verb YaDaH (Strong's #3034) derived from the word for hand/forearm YaD (Strong's #3027). It's also translated (40 times) as "thank" and (18 times) as "confess". 

Praise has always been demonstrated physically as well as verbally, even though often religiously repressed. I was worried of being branded as a heretic when I first tried it in my Baptist church, but it caught on like it was the most natural way to express praise. Once freed, the congregations I've been a part of haven't gone back to suppression. Good enough reason to get your hands up.