Canada’s Bank of Nova Scotia must be one of the few banks in the world that allows you to order gold bullion online. Visit their web site, punch in your order along with your credit card information, and a couple days later FedEx will deliver your gold to the door, all sealed up in a plain and boring little envelope.

The gold comes in bars, though not those massive gold bars you see in the movies. For somewhere around $1200 you could purchase a 1 ounce gold bar and have it delivered to your home. It would be 22mm wide, 38mm high and 2.3mm thick. You’d soon find that your dollar does not go far when you are using it to buy precious metals. What you would do with it once you buy it is a bit trickier—maybe you’d put it in a safe deposit box or maybe you’d just bury it out in the backyard. You probably wouldn’t want to carry it around in your pocket.

That 1 ounce gold bar is 24 karat gold, 99.99% pure. That is amazing when you stop to think about it. If it is 99.99% pure, it means that in order to divide out the impurities, you would need to divide it into equal 10,000 pieces before you found the one that was not gold. If the total surface area of that gold bar is 836mm, the impure part would come to less than one tenth of one millimeter. That would be smaller than the period at the end of this sentence. Do the calculation by weight and you’d find that it comes out to less than 3 milligrams.

This weekend my son was asking me about holiness, about what it means to be a sinner. He was having trouble distinguishing between what it means to do bad things to other people and what it means to be a sinner. He is only nine years old, not old enough to have experienced any significant trouble. He has never murdered, he has never stolen, he has never cursed the name of God. He may have done some bad things in his life, but honestly, he’s a pretty good kid. Isn’t that good enough? If we were to divide his life into 10,000 little thoughts and actions, might we find that only one in 10,000 was impure?

The problem, of course, is that God is not 99.99% pure and neither does he allow us to be “only” that pure. God is perfect—not mostly perfect, not almost entirely perfect, but absolutely, fully, purely perfect. And he made us to be like him, to be holy as he is holy. He gave us the ability to live in that holiness, to live so that 10,000 out of 10,000 thoughts and deeds were unblemished in any way. Though our first parents, acting on our behalf, saw fit to blemish that holiness, plunging us all into filth and defilement, the standard has removed unchanged. God demands and expects perfection. Any lack of perfection blemishes the entire person.

Ah, but here’s where we come to the heart of it. We cannot be perfect even though God demands perfection. And yet, out of his infinite grace, he has provided for us a substitute, one who was good on our behalf. He was good when he was born, free of the defilement of our parents; he was good as he walked the earth for three decades, free of the defilement of his own sin; he was good as he hung on the cross, even though there he became sin for us, taking on the full weight of our sin. And in the eyes of God, his sacrifice was good and sufficient. And now he offers to trade his holiness for our sin, if only we will trust in him.

It will be the answer to many, many prayers when my children look to this Savior, when they trade in their filth for his righteousness.