Theology is at its best when it takes weighty concepts and makes the connection to Christian life. Consider the debate over Christ’s impeccability. If you’re an eminently practical Christian, jostling over abstractions (Was Jesus not able to sin? -OR- Was Jesus able not to sin?) seems like a huge waste of time. Who cares how you explain it?!? The bottom line is Jesus didn’t sin.
More often than not the problem isn’t that the heavy discussions don’t matter but that we don’t know why they matter. The following passage on Christ’s impeccability is a good example of why seemingly esoteric discussions matter in the day-to-day [emphasis added]:
We may link the subject ‘God’ with many predicates. The Son of God may suffer, may be tempted, may be ignorant and may even die. But we cannot link God with the predicate ‘sin’. God cannot in any situation or for any purpose commit a transgression of his own will. He absolutely cannot be guilty of lawlessness.
It does not follow, however, that when Christ was tempted he was always aware, at the human level, that the Tempter could never conquer him. We know that the devil could, on occasion, put a big if against his consciousness of sonship (Mt 4:3). He would have found it equally easy to question his sinlessness. It would certainly be unwise to conclude that at every single point Jesus was in full possession of the whole truth about himself.
It is helpful to recall here Dr. John A. Mackay’s distinction between the view from the balcony and the view from the road. To the angels on the balcony (as to theologians in their armchairs) it may have been perfectly clear that Jesus could never sin. To himself, engaging the devil on the road, the outcome may have been far from clear. Never once, as we observe him struggle with temptation, do we see him deriving comfort from the fact of his own impeccability. All that we see is his having recourse to the very same weapons as are available to ourselves: the company of fellow-believers (Mk 14:33), the word of God (Mt 4:4) and prayer (Mk 14:35).
-Donald Macleod, The Person of Christ, 230.