Then Joshua son of Nun secretly sent two spies from Shittim. “Go, look over the land,” he said, “especially Jericho.”
So they went and entered the house of a prostitute named Rahab and stayed there. Joshua 2:1 (NIV)

In his book, The Great Boer War, Sir Arthur Conan Doyle recounts the story of a small detachment of British troops who were surprised by an overwhelming enemy force. The British fell back under heavy fire. Their wounded lay in a perilous position where they faced certain death. One of them, a corporal in the Ceylon Mounted Infantry, later told how they all realized they had to come immediately under the protection of a Red Cross flag if they wanted to survive. All they had was a piece of white cloth but no red paint. So they used the blood from their wounds to make a large cross on the white cloth. Their enemy, the Boers, respected that grim flag as it was held aloft, and the wounded British were brought to safety.

There’s a similar account in the Old Testament. A story of war, adventure, drama and intrigue – a story in which a small red flag was used to bring a family to safety in the midst of a bloody battle. You can read about it in Joshua 2:1-24; 6:1-27 but if you’ll allow me to exercise my imagination I’m going to launch into the drama and tell it from the innkeeper’s point of view:

“It was the seventh day of the siege. We were exhausted. The Israelites had been marching around and around the city, and now, as we peered out of the window, we saw seven priests putting trumpets to their lips. At the sound of a long shrill blast the Israeli soldiers let out a mighty roar. Almost simultaneously the city walls began to heave and shake. We were terrified! Our inn was part of the wall, and, as we huddled together, we could hear the grinding of masonry, the shattering of rocks, and the crack of splintering timbers as the wall collapsed. But miraculously, even when the adjoining sections of wall were torn away, our house stayed standing.

Then, through the billowing clouds of choking dust, we heard the cries of death. It was dreadful. Neighbours screaming in agony as tons of masonry pinned them down. Children shrieking in terror as they were put to the sword.

It wasn’t long before we heard another sound – soldiers scrambling up the collapsed wall toward the house. Fearing the worst, my sisters started crying and my brother began to retch. Then the door was kicked in and two blood splattered soldiers stood before us, weapons in hand. Terrified, we huddled together. The one soldier covered the exit as the other went to the window and reached through to untie the scarlet cord. With cord in hand he turned and smiled. It was only then that I recognized him as one of the two spies whom I had helped escape. I can’t begin to tell you how relieved I was. Our promised deliverance had arrived. We were safe because of the red flag.”

The story of Rahab’s salvation, although tremendous, is nothing compared to the blood of Jesus Christ being the ultimate scarlet thread. For Christ, in shedding His precious blood on Calvary’s cross is the eternal lifeline and guarantee of salvation for everyone who trusts in Him.

Which reminds me of a third story: General Stonewall Jackson and his Confederate troops were camping in the Shenandoah Valley of Virginia. They were expecting an attack from the Federal Army, so the order was given that no one would be allowed through the lines unless he could give the password. At midnight a poor wounded soldier approached the lines and was halted by a sentry. He was ordered to give the password or be shot on the spot. The boy had been left behind in a previous engagement and didn’t know the password. Feeling that death was near and remembering how he had been saved by Christ’s death on Calvary, he cried out, “The blood, the blood.” And the sentry said, “You may pass,” for that was the password that night.

It’s the same for us. Only one password will do – only one red flag is honoured. We are saved when we trust in the blood of Jesus Christ.