In Numbers 19 we learn about being free of defilement. We are in the world but not of it – we belong in the sanctuary. If we come into contact with evil, a remedy is required, otherwise communion will be hindered.
The blood of the unblemished heifer, represents Christ who knew no sin. The blood was sprinkled before the tabernacle (the place of communion) seven times. But the body of the heifer was reduced to ashes. This shows that we still have to understand the seriousness of sin, and what the Lord had to bear.
The person who had been defiled had to wait seven days for communion to be restored fully. He had to gather up the ashes – making him realise the horror of sin. In grace we get a sense of God’s perfect holiness that necessitated the sacrifice. We had been careless, and found ourselves outside of God’s presence. Now communion was restored.
This is a summary of a short article by John Nelson Darby. It is published in Collected Writings Volume 19 (Expository 1) page 292.