the driving force in Jesus' life

In chapter 18 of Knowing God, J. I. Packer writes the following...

Think first, then, of the driving force in the life of Jesus.

If you sit down for an hour and read straight through the Gospel according to Mark (a very fruitful exercise: may I urge you here and now to do it), you will receive an impression of Jesus which includes at least four features.

Your basic impression will be of a man of action: a man always on the move, always altering situations and precipitating things-working mir- acles; calling and training disciples; upsetting error that passed as truth and irreligion that passed as godliness; and finally walking straight and open-eyed into betrayal, condemnation and crucifixion (a freakish sequence of anomalies which in the oddest way one is made to feel that he himself controlled all along the line).

Your further impression will be of a man who knew himself to be a divine person (Son of God) fulfilling a messianic role (Son of Man). Mark makes it clear that the more Jesus gave himself to his disciples, the more of an awesome enigma they found him-the closer they came to him, the less they understood him. This sounds paradoxical, but it was strictly true, for as their acquaintance with him deepened they were brought closer to his own understanding of himself as God and Savior, and this was something of which they could make neither head nor tail. But Jesus' unique twofold self-consciousness, confirmed by his Father's voice from heaven at his baptism and transfiguration (1:11; 9:7) came out constantly. One has only to think here of, on the one hand, the breathtaking naturalness with which he assumed absolute authority in everything he said and did (see Mk 1:22, 27; 11:27-33), and on the other hand his answer to the high priest's double question at his trial, "Are you the Christ [Messiah, God's savior-king], the Son of the Blessed One [a supernatural and divine person]?" to which Jesus categorically replied, "I am" (14:61-62).

Going on from this, your impression will be of One whose messianic mission centered on his being put to death-One who was consciously and single-mindedly preparing to die in this way long before the idea of a suffering Messiah took hold of anyone else. Four times at least after Peter had hailed him as the Christ at Caesarea Philippi, Jesus predicted that he would be killed and rise, though without the disciples being able to make sense of what he said (8:31; compare vv. 34-35; 9:9; 9:31; 10:33- 34). At other times he spoke of his being put to death as something certain (12:8; 14:18, 24), something predicted in Scripture (14:21, 49), and something that would win for many a momentously new relationship with God. "The Son of Man [came] to give his life as a ransom for many" (10:45). "This is my blood of the covenant, which is poured out for many" (14:24).

-- J. I. Packer, "The Heart of the Gospel", in Knowing God, pp 191-92.