You wrote:
But lamb was on the table and He didn't choose to use that, even though He is "the Lamb of God". But He is also the bread of life; seems to be very considerate of Him to choose the most common of foods.It seems to me that Jesus used bread and wine because that is what was on the table.
He chose bread; He is the "decider" in this case, not us. And that is the nature of positive law - it is right because the one with authority, be it an elected government, king, or God says it is right. It has nothing to do with morality.Why is there significance in what he used?
It seems odd to me that evangelical Christians will not give an inch over what is right in regard to moral laws (as they should) but give great latitude when it comes to a positive law. Seems to me God cut some slack in the OT regarding moral laws (see David and Bathsheba) but in Saul's case where positive laws were violated God put the hammer down, not to mention the case of Uzzah, and many others, including Adam's sin.