A few quotes from Magisterium: Teacher and Guardian of the Faith (Sapientia Press, 2007), by Avery Cardinal Dulles, S.J.:
The propositions of faith are revealed truths; they are not the personal views of a particular theologian or school or theology. Academic theology is not, and does not claim to be, the word of God. Its theses do not merit the absolute assent of faith. Richly blessed though she is by her theologians, the Church needs in additional an office or organ capable of certifying revealed truth with divine authority. Otherwise she could not serve as "the pillar and bulwark of the truth" (1 Tim 3:15). The Magisterium is an essential resource for theology itself, for without it theology would lack a secure foundation on which to base its speculations. Theology seeks to understand as far as possible the truths that Christians believe as matters of faith.
The acceptance of a faith produced by a divinely commissioned witness is not, as some imagine, an abdication of personal responsibility. It is, on the contrary, a preeminently free and personal act. Freedom is given to us so that we may personally seek and embrace the truth, committing ourselves to live according to it. Since the truth that matters for salvation is offered to us by way of revelation, and since revelation is handed down by competent witnesses, our acceptance of these witnesses is inseparable from the act of faith itself. To withhold assent from the testimony of properly authenticated witnesses to revelation would be a misuse of freedom. (pp 5-6)
If we take the term "Magisterium" in this modern sense, it has to be understood as a function of the hierarchy, that is to say, the pope and the bishops, who succeed to Peter and the Apostles in teaching and pastoral rule. As we shall see in future chapters, there are many different modes of exercise of hierarchical teaching authority. Sometimes it is exercised by the whole body of bishops together with the pope as its head; sometimes by the pope alone; sometimes by individual bishops or groups of bishops. The exercise, moreover, can be more or less formal and solemn, resulting in different degrees of obligation on the part of the faithful to assent.
Once the term "Magisterium" is understood in its modern, narrow sense, as the power to teach officially in the name of Christ and to issue judgments binding on the faith of others, it becomes evident that theologians do not, as such, have a magisterial status. Their specific task is to penetrate and to explain the meaning, grounds, and implications of Christian faith. Although they strive to be of service in the Church, they are not mere servants of the hierarchy. Their primary responsibility is to discern and interpret the word of God by all the means available. In this role they are expected to do more than echo what the Magisterium has already taught, but they have no authority to oblige others to accept their conclusions. (p 39)
For all Christians, faith is something that comes by hearing, and what is heard comes by the preaching of Christ (Rom 10:17). Paul himself, as an Apostle, claims only to be relaying what he has heard. In his account of the Last Supper he emphatically makes the point that he has delivered to the Corinthians only what he himself received: "For I received from the Lord what I also delivered to you" (1 Cor 11:23). Again, in passing on the Resurrection kerygma, Paul writes: "For I delivered to you as of the first importance what I also received" (1 Cor 15:3). In these texts Paul uses the terms paradidonai and paralambanein, Greek equivalents for the terms used by the rabbis to describe the process of handing on and receiving the tradition. What the Apostle proclaims is the same as that which he received.
In the New Testament and in Christian theology, reception is not merely passive submission; it is a joyful and liberating response to the good news of the Gospel, a welcoming acceptance of the Lord. The Holy Spirit is both the transcendent source and the indwelling agent of reception. (p 102)
There is a normal human temptation to imagine that Christian unity can be achieved by compromise. If each party gives up some of its turf, we suppose, all may be able to stand together. But the truth of revelation is not a chip for bargaining. It is a precious trust that the Church is bound to preserve as the source of life for the world. The truth of God, if it is received, has a capacity for effecting unity far stronger than any natural ties. It breaks down all the natural, social, and cultural barriers by which people are ordinarily divided and makes them fellow-members of the one Body of Christ.
The Magisterium ranks among the ecclesial elements that keep the People of God in union with one another and their heavenly Lord. It cannot function except in subordination to Scripture and Tradition, and with the support of prayer and sacramental life. The pastors are no more than servants of communion. Like conductors of a choir, they must follow the score of the composer. They cannot function except when they find a responsive community, all of whose voices can blend into a harmonious chorus. As the Church, under their direction, sings the praises of the Lamb who sits upon the throne, she advances toward the eternal city in which no Magisterium will be needed, for all will see, with their own eyes, the mysteries in which they now believe. (pp 112-13)
• The History and Purpose of Apologetics | An Interview with Avery Cardinal Dulles, S.J.
• Foreword to Yves Congar's The Meaning of Tradition | Avery Cardinal Dulles, S.J.