The shape and density of a shadow has no substance. It is produced when light is removed by placing an object between the light source and a reflective surface. The writer describes the old covenant law in this way: as a shadow. Although it had appeared to be the ultimate way to please God, and devout Jews were obsessional in observing all the fine details, it was merely a back-projected image of something which was very real and substantial.

If the Old Testament system of sacrifices had ultimate substance, then they would not have needed to be repeated. But the sacrifice on the Day of Atonement did not remove sin – it only reminded the people that they were sinners and needed a totally effective sacrifice. Their own consciences recognised that because they still felt guilty. However many times sacrifices were made, they offered some comfort that God was not demanding full payment for their sins that year, but would require them to pay in the future. It was only a shadow of what Jesus would achieve perfectly (Colossians 2:17).

The shadow of the law had the shape of Jesus Christ. Although He was not revealed, the outline of what He would do was clearly seen. God's justice demanded the death of the sinner or a perfect sacrifice. Christ was that sacrifice and all the old covenant worship rituals looked forward to what He would do. The annual reminder of the people's sin was also an annual encouragement to look forward to the perfect sacrifice who would take their sin away, once and for all. The 'shadow' was a mystery before Jesus was revealed, but now it is made clear in the gospel (Romans 16:25).

So why do we seem to delight in shadows, preferring mysterious shapes rather than the true substance? Perhaps it is because the world of art invites us to read into what we see and formulate our own ideas about the painting or sculpture. As self-centred sinners, we like the idea of making God in our own image, to fit our world view – instead of us submitting to His. So religious mysteries with their rites and rituals are attractive. But the gospel is the revelation of God's mysteries, making clear that the old covenant is only a shadow and that the substance is in Jesus Christ. That is the message we must proclaim to our friends and colleagues (Ephesians 6:19).