What doe's law have on the blood?
What is sin?
1Jn 3:4 Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law.
And what does sin require?
Heb 9:22 And almost all things are by the law purged with blood; and without shedding of blood is no remission.
Sin requires blood.
The are inseparably related.