John Calvin Commentary Luke 22:19

"And he took bread, and when he had given thanks, he brake it, and gave to them, saying, This is my body which is given for you: this do in remembrance of me." — Luke 22:19 (ASV)

Which is given for you. The other two Evangelists leave out this clause, which, however, is far from being superfluous; for the reason why the flesh of Christ becomes bread to us is that by it salvation was once procured for us. And as the crucified flesh itself is of no advantage except to those who eat it by faith, so, on the other hand, the eating of it would be meaningless, and of hardly any value, if it were not in reference to the sacrifice which was once offered. Whoever then desires that the flesh of Christ should nourish him, let him look at it as having been offered on the cross, so that it might be the price of our reconciliation with God.

But what Matthew and Mark leave out in reference to the symbol of bread, they express in reference to the cup, saying that the blood was to be shed for the remission of sins; and this observation must be extended to both clauses. So then, in order that we may feed rightly on the flesh of Christ, we must contemplate its sacrifice, because it was necessary that it should have been once given for our salvation, so that it might be given to us every day.