Charles Spurgeon Commentary Luke 22:20

"And the cup in like manner after supper, saying, This cup is the new covenant in my blood, [even] that which is poured out for you." — Luke 22:20 (ASV)

Likewise also the cup after supper, saying, This cup is the new testament in my blood, which is shed for you.

He could not have meant that, literally, that cup was the new covenant; I never heard of anybody who thought he did. Why, then, take one part of the ordinance literally, if not the other? But our Lord did mean that the contents of that cup represented the blood, which seals and ratifies the eternal covenant on which our hopes are built.