I believe that the Scriptures are inspired and inerrant because the Catholic Church teaches that they are inspired and inerrant.
I believe in the Immaculate Conception and the Assumption of Mary because the Catholic Church teaches the Immaculate Conception and the Assumption of Mary.
The Immaculate Conception and the Assumption of Mary contradict nothing in Scripture, and they are reasonable in themselves.
No direct or categorical and stringent proof of the dogma can be brought forward from Scripture.
That right there in itself should cause the rcc to stop teaching this false doctrine.
Luke 1:28
The salutation of the angel Gabriel -- chaire kecharitomene, Hail, full of grace (Luke 1:28) indicates a unique abundance of grace, a supernatural, godlike state of soul, which finds its explanation only in the Immaculate Conception of Mary. But the term kecharitomene (full of grace) serves only as an illustration, not as a proof of the dogma.
We won't go into the incorrect translation of Luke 1:28 which should be Greetings, you favored with grace, or Greetings, favored one.
Other texts
From the texts Proverbs 8 and Ecclesiasticus 24 (which exalt the Wisdom of God and which in the liturgy are applied to Mary, the most beautiful work of God's Wisdom), or from the Canticle of Canticles (4:7, "Thou art all fair, O my love, and there is not a spot in thee"), no theological conclusion can be drawn. These passages, applied to the Mother of God, may be readily understood by those who know the privilege of Mary, but do not avail to prove the doctrine dogmatically, and are therefore omitted from the Constitution "Ineffabilis Deus". For the theologian it is a matter of conscience not to take an extreme position by applying to a creature texts which might imply the prerogatives of God.
In regard to the sinlessness of Mary the older Fathers are very cautious: some of them even seem to have been in error on this matter....
But these stray private opinions merely serve to show that theology is a progressive science.
This sounds eerily similar to Montanism. You will recall that it believed in ongoing revelation. Sure sounds like what the rcc is espousing with this doctrine and the assumption. You will recall it was one of the reasons the early church wanted a written canon.