This may be the wrong place for this, but I didn't know where else it might go.
I was thinking about how in OT times sacrificing something was their main form of worship. Whether it was grain, wine, animals, (leave out humans) the general idea was to give something to God that the person considered of value. Then I wondered if we're still doing some sort of sacrifice today for God? I think we are, but it's very different. Granted we don't burn up valuable things anymore, but we still make sacrifices for God. The main one that spurred me to make this thread was prayer. One thing most people consider of great value is their time. So when we dedicate time to praying to God there's an inherent sacrifice in it.
Thoughts or comments?