The LORD told Cain that the blood of his brother Abel cried out to God from the ground (Genesis 4:10).  

Both the Old and New Covenants between God and man are blood covenants (Genesis 15:1-18; Exodus 24:8; Heb 9:11-15)  

The LORD God told the original branch not to eat the blood of animals because life is in the blood (Deuteronomy 12:23).  

The Lord Jesus said, His was the blood of the New Covenant (Matthew 26:28; Mark 14:24; 1Co 11:25; Hebrews 9:20).  

The redemption and re-creation of mankind unto reconciliation with God the Father for our full restoration in right-standing, once for all, is by the blood of Jesus (Romans 3:25 & 5:9; Ephesians 1:7; Hebrews 9:12 & 10:10,26; 1Jn 2:2; Rev 1:5 & 5:9).  

The blood of Jesus cries out to His Father (Who became Our Father by His Blood), “MERCY!”