God is making sure we all understand that He doesn't need us to give Him goats or bulls. He owns the cattle on a thousand hills. What can we add to Him or give Him that He doesn't already have? NOTHING. (I've heard preachers and teachers use this verse to show how much God owns - how rich He is - and they'll say something like " God, I need some stuff. Could you sell one of your cows and give me the cash." But what God is saying through the psalmist here is that He already owns everything, why would we think He needs something from us?)
14 Sacrifice thank offerings to God, fulfill your vows to the Most High
Yes. Sin still has to be accounted for. Payment must be made. But if there is no change of heart they are pointless.
And of course the final payment for sin was made when Jesus gave His life on the cross.
So I think what I take from this Psalm is that God wants us to be thankful, do what we've promised to Him. He doesn't want meaningless words or sacrifices or offerings if there is no meaning behind them.
I could do another post on the beautiful imagery of the first few verses. I'll let these pictures share.