This passage mixes beautiful images of peace and regeneration with more disturbing themes about the nature of God's justice.
Years ago our family was toiling through an Alpine meadow in the hot sunshine when one of our children turned to us and asked, rather crossly, 'Why are you making us go through this barren wilderness?' It was an incredible thing to say because only someone walking with their head down could have failed to notice that, on both sides of the path – as far as the eye could see – there were literally millions of flowers of every colour and shade. If this was a wilderness, it was a wilderness which was rejoicing and blossoming like the one pictured by the Prophet.
In the prophet's vision, not only shall the wilderness blossom abundantly but the burning sand shall become like a pool, and the thirsty ground shall gush with springs of water. And this will be no empty mirage. The sparse desert grass will mutate into water-loving beds of reeds and rushes.
And there will be a special road through this flowering desert, a busy highway where no lions, jackals or ravenous beasts dare lie in wait for the lonely traveller. Joy and gladness will replace sorrow and sighing.
So far so good. But there is a jarring note in the prophecy. For the God who will come to strengthen the feeble and make the lame leap like a deer will also come with vengeance and terrible recompense. Some people will be saved, but others will be cut down. And the broad highway which leads to safety through the desert will be a holy way. Although it will be so straight and easy to follow that no one will need a map or satellite navigation to negotiate it, the unclean will not be allowed to travel on it at all. Only the redeemed shall walk there.
If this were a description of heaven, or of the Kingdom of God, there would be nothing wrong with this picture. But it isn't. It's meant to be a picture of our world, but it's a picture in which some people find peace and prosperity while others are excluded. It's the sort of picture of righteousness and justice which inspired the people who built a huge fence between Israel and Palestine, so that they could keep the suicide bombers, but also many ordinary Palestinians, on the outside.
And, of course, it's not a Christian image, for Jesus made it very clear that – at least for the time being – God is determined not to choose between the good and the bad. One day there will indeed come a time for judgement but, until then, the struggle goes on to persuade everyone to choose the right way. Being holy doesn't mean shutting some people out because they are considered unclean, it means welcoming everybody in and trying to convince them to be made holy too.