The once and future tense

Why has the future tense come to displace the present in certain renditions of the Words of Institution?

“This is my body which will be given up for you”?

Weak tea, I say. Count me firmly in the camp of “This is my body which is given up (or, better, which is broken for you).” Christ’s sacrifice is not merely some innerworldly event, since the Lamb is slain at the foundation of the cosmos. This is eternally so, though disclosed in time, not merely the foreshadowing of an event confined to such and such a place and time.

What Jesus is in his very being is the breaking open of human nature to divinization.