"578 Jesus, Israel's Messiah and therefore the greatest in the kingdom of heaven, was to fulfill the Law by keeping it in its all embracing detail - according to his own words, down to "the least of these commandments".330 He is in fact the only one who could keep it perfectly.331 On their own admission the Jews were never able to observe the Law in its entirety without violating the least of its precepts.332 This is why every year on the Day of Atonement the children of Israel ask God's forgiveness for their transgressions of the Law. The Law indeed makes up one inseparable whole, and St. James recalls, "Whoever keeps the whole law but fails in one point has become guilty of all of it."333
493 The Fathers of the Eastern tradition call the Mother of God "the All-Holy" (Panagia), and celebrate her as "free from any stain of sin, as though fashioned by the Holy Spirit and formed as a new creature".138 By the grace of God Mary remained free of every personal sin her whole life long.
Sin is defined as breaking the law of God.
Which is true? Was Jesus the ONLY one that could fulfill all the Law (not sin) or not?
That's why Gabriel called her "Full of Grace."
I. JESUS AND THE LAW
577 At the beginning of the Sermon on the Mount Jesus issued a solemn warning in which he presented God’s law, given on Sinai during the first covenant, in light of the grace of the New Covenant:
Do not think that I have come to abolish the law or the prophets: I have come not to abolish but to fulfill. For truly I tell you, until heaven and earth pass away, not one letter, not one stroke of a letter, will pass from the law, until all is accomplished. Therefore, whoever breaks one of the least of these commandments, and teaches others to do the same, will be called least in the kingdom of heaven; but whoever does them and teaches them will be called great in the kingdom of heaven.329
578 Jesus, Israel’s Messiah and therefore the greatest in the kingdom of heaven, was to fulfill the Law by keeping it in its all embracing detail - according to his own words, down to “the least of these commandments”.330 He is in fact the only one who could keep it perfectly.331 On their own admission the Jews were never able to observe the Law in its entirety without violating the least of its precepts.332 This is why every year on the Day of Atonement the children of Israel ask God’s forgiveness for their transgressions of the Law. The Law indeed makes up one inseparable whole, and St. James recalls, “Whoever keeps the whole law but fails in one point has become guilty of all of it.”333
579 This principle of integral observance of the Law not only in letter but in spirit was dear to the Pharisees. By giving Israel this principle they had led many Jews of Jesus’ time to an extreme religious zeal.334 This zeal, were it not to lapse into “hypocritical” casuistry,335 could only prepare the People for the unprecedented intervention of God through the perfect fulfillment of the Law by the only Righteous One in place of all sinners.
Taking stuff out of context could be misconstrued as bearing false witness. But I will happily leave that conversation to you and Our Lord, Jesus Christ.
“Rejoice, you who are full of grace”
721 Mary, the all-holy ever-virgin Mother of God, is the masterwork of the mission of the Son and the Spirit in the fullness of time. For the first time in the plan of salvation and because his Spirit had prepared her, the Father found the dwelling place where his Son and his Spirit could dwell among men. In this sense the Church’s Tradition has often read the most beautiful texts on wisdom in relation to Mary.101 Mary is acclaimed and represented in the liturgy as the “Seat of Wisdom.”
In her, the “wonders of God” that the Spirit was to fulfill in Christ and the Church began to be manifested:
722 The Holy Spirit prepared Mary by his grace. It was fitting that the mother of him in whom “the whole fullness of deity dwells bodily”102 should herself be “full of grace.” She was, by sheer grace, conceived without sin as the most humble of creatures, the most capable of welcoming the inexpressible gift of the Almighty. It was quite correct for the angel Gabriel to greet her as the “Daughter of Zion”: “Rejoice.”103 It is the thanksgiving of the whole People of God, and thus of the Church, which Mary in her canticle104 lifts up to the Father in the Holy Spirit while carrying within her the eternal Son.
723 In Mary, the Holy Spirit fulfills the plan of the Father’s loving goodness. Through the Holy Spirit, the Virgin conceives and gives birth to the Son of God. By the Holy Spirit’s power and her faith, her virginity became uniquely fruitful.105
724 In Mary, the Holy Spirit manifests the Son of the Father, now become the Son of the Virgin. She is the burning bush of the definitive theophany. Filled with the Holy Spirit she makes the Word visible in the humility of his flesh. It is to the poor and the first representatives of the gentiles that she makes him known.106
725 Finally, through Mary, the Holy Spirit begins to bring men, the objects of God’s merciful love,107 into communion with Christ. And the humble are always the first to accept him: shepherds, magi, Simeon and Anna, the bride and groom at Cana, and the first disciples.
726 At the end of this mission of the Spirit, Mary became the Woman, the new Eve (”mother of the living”), the mother of the “whole Christ.”108 As such, she was present with the Twelve, who “with one accord devoted themselves to prayer,”109 at the dawn of the “end time” which the Spirit was to inaugurate on the morning of Pentecost with the manifestation of the Church.
Contradiction? Nope, not in any fashion.