The planners of the D-Day landings in 1944 faced a problem: previous similar invasions, had led to frequent incidents of ‘friendly fire’. Unable to distinguish between Allied and enemy aircraft in the heat of battle, there were numerous occasions when Allied forces on the ground mistakenly fired on their own aircraft.
The problem was overcome by the simple expedient of painting three white rings around the wings and fuselage of the thousands of Allied aircraft involved in D-Day. In fact every last drop of white paint in the country was used for the purpose.
Of course it’s not the first time that significant markings have been used to avoid the problem of ‘friendly fire’. On the night before God acted decisively to free his people from 400 years of slavery in Egypt, they were commanded to daub the doorframes of their houses with the blood of a lamb, so that God’s Angel of Judgement would ‘pass over’ them. This act of salvation echoed down the centuries and found its ultimate fulfilment in the sacrifice of Jesus on a cross, willingly shedding His blood in order to reconcile us to God. No wonder John the Baptist greeted Him with these words, “Behold the Lamb of God.”