The blood on the doorposts marked the houses as those who believed and obeyed in order that they would be free from slavery.
The death of the lamb
Shed the blood
Which was the sign
Of those who believed
(Heart)
And obeyed
(Action)
So that
They could be free
(Result)
Without belief – it’s salvation by works (religion).
Without obedience, there is no evidence ∴ no belief.
Without the blood, there is no sign.
Without the sacrifice there’s no blood to apply.
Without the death of the lamb there is no way.
To freedom from the bonds or wounds of sin.
Not past (Exodus 12).
Not now.
Jesus.