Those who deny the Church a final teaching competence in this area force her to remain silent precisely where the boundary between truth and lies is at stake.
Independently of this question, in many circles of moral theology the hypothesis was expounded that the Church does not and cannot have her own morality. The argument being that all moral hypotheses would also know parallels in other religions and therefore a Christian property of morality could not exist. But the question of the unique nature of a biblical morality is not answered by the fact that for every single sentence somewhere, a parallel can also be found in other religions. Rather, it is about the whole of biblical morality, which as such is new and different from its individual parts.
The moral doctrine of Holy Scripture has its uniqueness ultimately predicated in its cleaving to the image of God, in faith in the one God who showed himself in Jesus Christ and who lived as a human being. The Decalogue is an application of the biblical faith in God to human life. The image of God and morality belong together and thus result in the particular change of the Christian attitude towards the world and human life. Moreover, Christianity has been described from the beginning with the word hodós [Greek for a road, in the New Testament often used in the sense of a path of progress].
Faith is a journey and a way of life. In the old Church, the catechumenate was created as a habitat against an increasingly demoralized culture, in which the distinctive and fresh aspects of the Christian way of life were practiced and at the same time protected from the common way of life. I think that even today something like catechumenal communities are necessary so that Christian life can assert itself in its own way. – from the Pope Emeritus’ 2019 letter on the abuse crisis