Why Get Baptized?

Why get baptized? -or - One way to demonstrate your faith.

Romans 10:9,10 says we should confess and believe.  (only)
Acts 16:31 says we should believe.  (only)
The thief on the cross did not get baptized, as found in Luke 23:39-43.

Then what need is there to get baptized?

However,
Acts 2:38 says we should repent and be baptized.

Yes or no?

One way to connect or reconcile these two thoughts is found in James 2:14-26 "Show me your faith by your works."

The idea I'm pulling out of James 2 is this:
Faith needs to be demonstrated and baptism demonstrates faith.

Larry Carroll