Perhaps it is not a good idea to be too disdainful about the Novus Ordo Calendar simply because it places the Feast of the Immaculate Heart of Mary on the Saturday after the Sacred Heart, instead of on the (old) Octave Day of the Assumption (which is where Pius XII was to place it). In the 1938 Carmelite Rite ... the last edition of that Rite before the Conciliar period ... this was the date for the feast of the Most Pure Heart of Mary. So, in places like Lanherne, where the pre-Conciliar Carmelite Rite is in use ... ... In any case, this year, at least, the Saturday after the Sacred Heart is free for a Votive of Mary's Heart (nudge nudge). In an 1879 Missal on my shelves, the Appendix provides a Feast of our Lady's Most Pure Heart on Sunday (Pentecost III, tomorrow); the collects, but not the readings, are the same as those of Pius XII. You will have noticed that neither the Carmelites nor the Js had changed Purissimi to Immaculati, despite the Definition of 1854. I wonder what the history of this alteration is. I argue below that the term 'immaculate' has more biblical, Hebraic, resonances than 'most pure'.
Pope Benedict (I hope you've said a prayer for his brother George) once observed, with his deft and agreeable irony, that "people from the Anglo-Saxon and German cultural world" tend to feel uneasy about devotion to the Immaculate Heart of our Blessed Lady. He goes on to point out that "In Biblical language, the Heart [Leb] indicates the centre of human life, the point where reason, will, and temperamentand sensitivity converge, where the person finds his unity and his interior orientation. According to Matthew 5:8, the 'immaculate heart' is a heart which, with God's grace, has come to a perfect unity and therefore 'sees God'. To be 'devoted' to the Immaculate Heart of Mary means therefore to embrace this attitude of heart, which makes the fiat - 'your will be done' - the defining centre of one's whole life".
The liturgical celebration of Mary's Heart was, for quite a time, resisted and discouraged by the Roman authorities. It made its way, not by being forced downwards by centralising liturgical Authorities who Know Best, but by forcing its way upwards, from the plebs sancta Dei, the worshipping community.
This entire way of speaking, far from being a piece of sickly Southern-European sentimentality, is rooted from beginning to end in the Scriptures both of the Old and of the New Testaments. But this devotion did not generally arise as an academic response to Biblical texts and themes. The religious and the mediterranean peasants and priests among whom these usages flowered, were simply, instinctively, naturally, organically and healthily nurtured by the Christian and Biblical tradition. And the fact that their devotion is so congruous with Biblical themes is a pretty obvious guarantee of the wholesomeness of their religion.
Psalm 180:80 speaks of a heart which is (MT; LXX; Vg) tamim; amomos; immaculatum. This word frequently applies to sacrificial animals (BDB says "Exodus 12:5 and 40 times; Ezekiel 43:22 and 10 times"). We are not to offer what is faulty to YHWH, any more than we would give a defective animal to the King. Sacrifice is not a system for disposing of imperfect or moribund members of the flock! BDB goes on to say "sound, wholesome, unimpaired, innocent, having integrity: of God's way ... work ... Law ... etc.". So our Heart is to be good enough to offer to YHWH in sacrifice; as sound as His Torah and as His creative providence. It is because Mary's Heart is attuned to Him (Luke 1:38; 2:19; 2:51 ... how many more instances could Biblicists desire?) and to the needs of others (John 2:3), even before the Hour of the Lord's Glory (John 2:4), that the intercession of her heart mediates through shared obedience (John 2:5) the first Sign of the fullness of the Kingdom (John 2:11) - that Sign which is the arche, fount and source, of all his other signs (C K Barrett: a primary sign, because representative of the creative and transforming work of Jesus as a whole).
Perhaps there is significance in the Cleansing of the Temple which follows immediately in S John's narrative: because the Word has transformed Water (the Old Covenant) into Wine (the New), this definitive transformation now has to be actualised in the replacement of the Old Temple by the New.