Man, I've read The Cross of Christ three times now, and it still so good.
On the Last Supper, and the need to appropriate the death of Christ personally:
"Again He took and blessed the cup, but then he explained its meaning as he gave it to them to drink. Thus they were not just spectators of this drama of the cross; they were participants in it. They can hardly have failed to get the message. Just as it was not enough for the bread to be broken and the wine to be poured out, but they had to eat and drink, so it was not enough for him to die, but they had to appropriate the benefits of his death personally. The eating and drinking were, as still are, a vivid acted parable of receiving Christ as our crucified Saviour and of feeding on him in our hearts by faith." (cf. Jn. 6:53-55)