To borrow an expression from an old-timer Priest who had spent years working with young folks in various US big cities – "sin is in the blood", in other words, in the passions of the heart – is an obvious fact that is totally ignored by men. Yet who can deny that when you are angry, your blood boils, and when you are afraid, it freezes. Again, when impurity attacks the soul, it attacks through the blood. Our blood and our thoughts are so intimately united and reciprocally connected that a split-second difference is hard to notice. This fact is so real that God has given us a special virtue, continency, to withstand the violent assaults of the blood.
To redeem man fundamentally, to change him from the inside out, requires a deep re-vamping of human nature in its deepest constituents – soul and blood. What a remarkable act of Divine Mercy and what supernatural wisdom in the truth that we are redeemed by the Blood of Christ. His Blood in a washing stream cleanses our very soul from the nearly indelible stain of sin. By that close connection with the soul, blood becomes the instrument of Grace to touch man's very soul.
Still deeper in this mystery, the Blood of Christ comes from the blood of Mary. Divine Wisdom considered: "Shall I clean blood stained by Original sin or shall I protect it altogether from that stain?" God the Father, for the honor of the Divine Name, who "both glorified it and will glorify it again", chose to protect Mary pure, never to allow Her to be for even a single instant the property of Satan, and to provide a perfect Mother for His only begotten Son. And so, at the Incarnation, Mary's immaculate blood mixed with the Precious Blood and the Divinity coursed through the world in Her virginal womb.
Our life must imitate Mary's in its deepest parts. The Blood of Christ must purify our souls in Baptism and Confession, and then it must flow in us by the Holy Eucharist. As it flowed in Mary's for 9 months, so it flows in ours for a few minutes after Holy Communion. And as Mary's spiritual union with Christ lasted and deepened every day, so it must be in us.
But how? The profound spiritual union with Christ, right down to our blood-animated instinct and reactions can only come by a continual Marian discipline. We do this firstly by imitating Her desire for the Glory and the Kingdom of God in all that we do and say: "My soul magnifies the Lord". This is where all Justice, social and private begins. Secondly, we do this by practicing Her Humility: "He has regarded the humility of his handmaid." We must repent our faults and rise again, with the help of Her prayers. Ave Maria!