Behold, I send my messenger to prepare the way before me, and the Lord whom you seek will suddenly come to his temple; the messenger of the covenant in whom you delight, behold, he is coming, says the LORD of hosts. But who can endure the day of his coming, and who can stand when he appears? For he is like a refiner's fire and like fullers' soap.
We live in a time when professional theologians are busy explaining God away. It's all a myth and a way of explaining our need to create meaning for ourselves ("Man's Search for God"). Malachi reminds us that now and then, God actually shows up–an eventuality we usually don't really intend to happen. The day came when God did indeed send his messenger to prepare the way before him. We cut his head off. Then the Lord himself suddenly came to the Temple–and turned over the tables of the moneychangers in his wrath. It was unendurable. So we killed him. We couldn't stand him and we still can't–which is why there are so many theologians around to tell us what our itching ears want to hear. But he came back anyway and he's been refining us with fire and washing us clean in baptism ever since.