Seeing the blood...

"But the blood will mark the houses where you are.
Seeing the blood, I will pass over you; 
thus, when I strike the land of Egypt, 
no destructive blow will come upon you."

God the Father asked Moses to mark the doorways of His Chosen People with the blood that drained out of the sacrificial lambs.  Upon seeing this blood, the Angel of Death was instructed to pass that household by, as it had already offered it's sacrifice.

During the Last Supper, Jesus started to make it clear that HE was to be our sacrifice.  

"Then he took a cup, gave thanks, and gave it to them, and they all drank from it. He said to them, “This is my blood of the covenant, which will be shed^* for many."

During Matthew's version of the crucifixion, Pilate wanted to set Jesus free, 'And all the people said, "His blood shall be on us and on our children!"'

So in order to be passed over by the Angel of Death, my doorways require the blood of the sacrifice.  Jesus was that sacrifice, and provided the blood of a new covenant.  His blood was shed for many, and all the people begged and cried out for His blood to be upon them and their children.

I beg this same thing, Lord. 

 May your blood be upon the doorposts of my heart, and those of my children.  As you take up your place on the Cross, covered with the sweat and pain of bearing my sinfulness and each blow that I deserve tears into your flesh, may those precious drops of blood be upon the doorposts of my soul, protecting me from harm.  Let YOUR sinless, precious blood proclaim to all who see it that the sacrifice has been made. May it go before me into every place I enter. May it follow my children, and their children to untold generations, purifying their souls as they give their faith, hope and love to you. 

Lord, you shed the blood.  Please mark my house.  Please pass over us in your wrath, but enter and stay with your love.  When you see the blood, know you are welcome here.