Red. The color of salvation, declaring the triumphant redemption of mens' souls through the blood of Jesus Christ. Revelation 5:12 Saying with a loud voice, "Worthy is the Lamb that was slain to receive power, and riches, and wisdom, and strength, and honor, and glory, and blessing." Nobody else can do what Jesus did for me and you.
Exodus 12:13 And the blood shall be to you for a token upon the houses where you are: and when I see the blood, I will pass over you, and the plague shall not be upon you to destroy you, when I smite the land of Egypt. A token, a symbol of the salvation through Christ that was yet to happen.
Job proclaimed it first when he said, "I know my Redeemer lives." Yes, my Redeemer lives. And He lives in me.