Must it be admitted that Christ instituted His Church as the official and authentic organ to transmit and explain in virtue of Divine authority the Revelation made to men?
The Protestant principle is: The Bible and nothing but the Bible; the Bible, according to them, is the sole theological source; there are no revealed truths save the truths contained in the Bible; according to them the Bible is the sole rule of faith: by it and by it alone should all dogmatic questions be solved; it is the only binding authority.
Catholics, on the other hand, hold that there may be, that there is in fact, and that there must of necessity be certain revealed truths apart from those contained in the Bible; they hold furthermore that Jesus Christ has established in fact, and that to adapt the means to the end He should have established, a living organ as much to transmit Scripture and written Revelation as to place revealed truth within reach of everyone always and everywhere.
Such are in this respect the two main points of controversy between Catholics and so-called orthodox Protestants (as distinguished from liberal Protestants, who admit neither supernatural Revelation nor the authority of the Bible). The other differences are connected with these or follow from them, as also the differences between different Protestant sects--according as they are more or less faithful to the Protestant principle, they recede from or approach the Catholic position.
Between Catholics and the Christian sects of the East there are not the same fundamental differences, since both sides admit the Divine institution and Divine authority of the Church with the more or less living and explicit sense of its infallibility and indefectibility and its other teaching prerogatives, but there are contentions concerning the bearers of the authority, the organic unity of the teaching body, the infallibility of the pope, and the existence and nature of dogmatic development in the transmission of revealed truth.
Nevertheless the theology of tradition does not consist altogether in controversy and discussions with adversaries. Many questions arise in this respect for every Catholic who wishes to give an exact account of his belief and the principles he professes: What is the precise relation between oral tradition and the revealed truths in the Bible and that between the living magisterium and the inspired Scriptures? May new truths enter the current of tradition, and what is the part of the magisterium with regard to revelations which God may yet make? How is this official magisterium organized, and how is it to recognize a Divine tradition or revealed truth? What is its proper rôle with regard to tradition? Where and how are revealed truths preserved and transmitted? What befalls the deposit of tradition in its transmission through the ages?
From the Catholic Encyclopedia.
Just to lay out the different views.
Yes. As Jesus Christ prayed (John 17) to His Father before His crucifixion: "And this is eternal life, that they may know Thee, the only true God, and Jesus Christ whom Thou hast sent... I manifested Thy name to the men whom Thou gavest Me out of the world; Thine they were, and Thou gavest them to Me, and they have kept Thy word... for the words which Thou gavest Me I have given to them, and they received them... I have given them Thy word, and the world has hated them because they are not of the world, even as I am not of the world... Sanctify them in the truth; Thy word is truth... And for their sakes I sanctify Myself, that they themselves also may be sanctified in truth..."
or can it, must it, be admitted that Christ gave to His Apostles to be transmitted to His Church, that the Apostles received either from the very lips of Jesus or from inspiration or Revelation, Divine instructions which they transmitted to the Church and which were not committed to the inspired writings?
No, no such thing "can," "must" be admitted. All divine instruction was committed to writing, as this is the way it had always been ordered by God.
Catholics... hold that there must of necessity be certain revealed truths apart from those contained in the Bible.
OH? Exactly what did God leave out that catholics say are necessary?
...they hold furthermore that Jesus Christ has established... a living organ as much to transmit Scripture and written Revelation as to place revealed truth within reach of everyone always and everywhere.
And this "living organ" they call the catholic church. According to God's word, the living organ who reveals truth is the Holy Spirit, not a visible, hierarchal church. "For to us God revealed them through the Spirit; for the Spirit searches all things, even the depths of God... We have the mind of Christ." 1 Cor. 2:16
(Roman catholic church, get over yourself.)