"What do I come in for, you say, if I do not hear some one discoursing? This is the ruin and destruction of all. For what need of a person to discourse? This necessity arises from our sloth. Wherefore any necessity for a homily? All things are clear and open that are in the divine Scriptures; the necessary things are all plain. But because ye are hearers for pleasure’s sake, for that reason also you seek these things. For tell me, with what pomp of words did Paul speak? and yet he converted the world. Or with what the unlettered Peter? But I know not, you say, the things that are contained in the Scriptures. Why? For are they spoken in Hebrew? Are they in Latin, or in foreign tongues? Are they not in Greek? But they are expressed obscurely, you say: What is it that is obscure? Tell me. Are there not histories? For (of course) you know the plain parts, in that you enquire about the obscure. There are numberless histories in the Scriptures. Tell me one of these. But you cannot. These things are an excuse, and mere words."
From Nicene and Post-Nicene Fathers (ed. Schaff), Series 1, Vol XIII, Sermons of St Chrysostom on Galatians, Ephesians etc., Sermon III on 2 Thessalonians 1:9-10, para 388.
The language is rather archaic but the meaning is clear enough: in a rhetorical dialogue with his congregation, whom he suspects of coming to hear him preach merely 'for pleasure', the 'Golden Mouthed' preacher of the ancient church chastises his hearers for their slothfulness in applying themselves to the study of holy scripture, whence arises the need for discourses or homilies in the first place. These should not be necessary, Chrysostom suggests, since "all things are clear and open that are in the divine scriptures; the necessary things are all plain".
By way of comparison to Lutheran orthodoxy, we quote from Abraham Calov (1612-1686), who comes very close to repeating exactly Chrysostom's thought, although in the language of dogmatics: "in those things which are necessary to be known in order to salvation, the Scriptures are abundantly and admirably explicit, both by the intention of God their author, and by the natural signification of the words, so that they need no external and adventitious light" [Systema Locorum Theologicorum, Vol 1, p.467, quoted also in Schmid, Doctrinal Theology of the Evangelical Lutheran Church, (Augsburg, Minneapolis, 1961, p.68).
Of course, there is more that can be said, including the following...
The Fourth Session of the Council of Trent, which set forth Rome's official response to the magisterial Reformation's doctrine of scripture, did not explicitly condemn this view of the clarity of scripture, although a rejection of the Reformation doctrine might be regarded as implicit in Trent's attempts to limit the free publication and interpretation of holy scripture apart from the permission and authority of the Roman church. Much later, in his encyclical Providentissimus Deus (1893), Pope Leo XIII said that scripture was somewhat wrapped in obscurity and therefore the authoritative guidance of the church was necessary to a right understanding of it, which we can regard as the official Roman position.
Roman Catholic apologists will often point to the multiplicity of "Protestant sects" as a practical argument against the clarity of scripture, but this response fails to take into account the orthodox distinction between internal and external clarity of scripture and the noetic impact of sin on the human interpreter, a reality of which the Lutheran theologians were highly cognisant. Indeed, that is why they developed the strictly historical-grammatical hermeneutic which is much more sober than either the allegorical flights of fancy of many of the Fathers or the later, highly speculative "assured results" of higher criticism, not to mention the 'doctrinal positivism' of the Papacy, which asserts dogmas of the faith to be believed by all on pain of loss of salvation without scriptural support at all.
The Roman Catholic apologist also typically ignores the large degree of consensus that the confessions which came out of the magisterial Reformation (Lutheran, Anglican, Reformed) have on the fundamental articles of faith (i.e. original sin, justification, scripture, etc), a consensus which was not apparent among the Fathers at Trent, let it be said. Also, where ecclesiastical authority is properly understood and ordered as subordinate to the scriptures, Reformation theology has no objection to a role for the church as guide and teacher (the formal principle of the Lutheran Reformation is sola scriptura, not solo scriptura!). That is one of the reasons why we have creeds, confessions and the preaching office.
In fact, the typical Roman Catholic apologetic position on the issue of the clarity of scripture and the absolute need for supplementary teaching by the church is fraught with difficulties itself. The oft-heard appeal to the Fathers as authoritative teachers can lead to some very "Protestant" opinions being uncovered (pardon the anachronism), as the citation from Chrysostom shows (see others at the blog Lutheran Catholicity - click on the post title). As for the much lauded consensus of the Fathers on doctrinal issues that many Roman apologists point to, it is difficult, if not impossible to locate; and just where can the deposit of the "authoritative interpretation of scripture by the church" to which we are urged to look for certainty be found? Such a deposit does not exist as far as we can determine, or if it does, it is scattered and hidden among two thousand years worth of theologising. Of what practical use to the Christian is a rule of faith whose contents cannot be identified? We are effectively left with the proverbial "coal miner's faith": "Q. What do you believe? A. I believe what holy mother church believes. Q. And what does your church believe? A. Holy mother church believes what I believe"!
Finally, Luther's experience of the late medieval church can be pointed to as the prime example of where the authoritative guidance of the church has dimmed, rather than enlightened Christendom as to the glorious Gospel of Jesus Christ. Indeed, Luther's twin re-discoveries of the authority and clarity of God's Word (sola scriptura) and the good news that we are justified freely by God's grace on account of faith in Christ (sola gratia, sola fide) are the nexus out of which the Reformation came to be and through which God was allowed to be God once again!
Soli Deo Gloria!