It is well attested that Calvin wrote his Institutes to stimulate his readers to read his commentaries and, therefore, reflect deeply on the Scriptures themselves. This is clearly evident from the familiar words Calvin addressed to the reader:
“Moreover, it has been my purpose in this labor to prepare and instruct candidates in sacred theology for the reading of the divine Word, in order that they may be able both to have easy access to it and to advance in it without stumbling. For I believe I have so embraced the sum of religion in all its parts, and have arranged it in such an order, that if anyone rightly grasps it, it will not be difficult for him to determine what he ought especially to seek in Scripture, and to what end he ought to relate its contents. If, after this road has, as it were, been paved, I shall publish any interpretations of Scripture, I shall always condense them, because I shall have no need to undertake long doctrinal discussions, and to digress into commonplaces. In this way the godly reader will be spared great annoyance and boredom, provided he approach Scripture armed with a knowledge of the present work, as a necessary tool” (John T. McNeill (ed.), Calvin: Institutes of the Christian Religion vol 1, (Louisville: John Knox Press, 2006), pp 4,5)
It is clear that Calvin viewed the Institutes as a “necessary tool” or hermeneutical guide for reading Scripture. In this connection, Ganoczy has expressed the link between Calvin’s Institutes and the text of Scripture in terms of the “first hermeneutical circle” (Alexandre Ganoczy, “Calvin als paulinischer Theologe”, in Wilhelm Neuser (ed.), Calvinus Theologus, (Neukirchen, 1976), pp 39-69. “Hermeneutical circle” is used in the abstract to translate ‘hermeneutisch Leitfaden’). Scripture and the Spirit constitute a “second hermeneutical circle”. Such a ‘hermeneutical circle’ is evident in Calvin’s comment on Romans 3:28 where, in the context of alluding to the epistle of James and the meaning of justification, he urges the reader, “On this subject, see my Institutes” (John Calvin (translator: Ross Mackenzie), The Epistles of Paul the Apostle to the Romans and to the Thessalonians, (Grand Rapids: Eerdmans, 1976), p 79).
Calvin was concerned that the Institutes guide his readers through what he referred to as the “labyrinth” of the Scriptures. Thus the concept of sola scriptura was somewhat nuanced.
Bullinger, on the other hand, was concerned that his readers develop the skills to rightly interpret Scripture. His starting point was the perspicuity of Scripture. He believed that God communicates to men and women intelligibly and that this can be discerned through judicious application of rhetoric in interpreting Scripture. Thus, in his commentaries, Bullinger did not deal with every textual or philological detail (contra, for example, Bucer’s commentary on Romans). Bullinger sought to write in a manner characterized by brevity, faithfully pointing out the major thread of the arguments of the particular book of Scripture. In his commentaries Bullinger sought to give a concise overview of the major themes on the book (eg a Pauline epistle) with a view that his commentaries would be aids to assist the reader to preach the message of the book from the pulpit. This accords with Bullinger’s emphasis that to preach the Word of God is the Word of God (Praedicatio verbi Dei est verbum Dei).
The message of the Bible as a whole from the stand point of biblical theology is reflected in particular works of Bullinger that would have been in the hands of the pastors he targeted, viz De Testamento, der alt gloub, The Decades and the Summa christenlicher Religion. His strategy was for his readers to be familiar with these works and, therefore, of the overall message of Scripture. Bullinger expected his readers to draw the lines, as it were, linking his various works which would have been in their hands.
This can be illustrated from the following quote from The Decades 3.viii:
“Touching the likeness and agreement, the unlikeness and difference of both, I mean, the old and new testaments or people, I have therefore spoken the more briefly, because I have in the first sermon of the first decade, and in the sixth sermon of the third decade, aleady handled the selfsame matter. Finally, I have but shortly touched the abrogation of the law, because I did a good while ago set forth two treatises; the one Of the ancient faith, the other Of the only and eternal covenant of God; which treatises I know to be familiar among you”. (Parker Edition p299)
Here, Bullinger directly refers to der alt gloub which was translated into English as The Old Faith. He also refers to De Testamento which, strangely, was not translated into English.
The Latin of the above quote is:
Paucioribus haec de similitudine et congrentia, item de discrimine et differentia utriusque tam veteris quam novi populi et testamenti perstrinxi, quod hoc negotii attigerim sermone 1. Decadis 1., item sermone 6. Decadis 3. denique in negotio de abrogatione legis et quod olim quoque de antiqua fide et de unico aeternoque dei testamento tractatus ediderim, quos scio vobis esse familiarissimos. (Peter Opitz, Sermonum Decades, p412)
The modern German translation is:
Nur kurz habe ich geredet über die Ähnlichkeit und Gleichheit aber auch über die Unterschiede beider Testamente und beider Bundesvölker, des alten und des neuen, weil ich dieses Thema schon in der ersten Predigt der ersten Dekade, dann in der sechsten Predigt der dritten Dekade und schließlich in der Abhandlung über die Aufhebung des Gestzes angeschnitten habe, und weil ich bereits früher Abhandlungen veröffentlicht habe über den alten Glauben und über das einzige und ewige Testament Gottes, von denen ich weiß, dass sie euch wohl bekannt sind. (Heinrich Bullinger Schriften, TVZ 2006, p133,134)