491-6, and that contained in the Marietti edition of the Opuscula Theologica by R. A. Verardo (Turin, 1954), I pp. 441-3.
Thomas returned to the subject of prayer over and over again in the course of his writings; it seems to have been a subject that interested him, and it is certainly a subject on which he achieved a degree of clarity it would be hard to parallel in any other theologian. And the treatise on prayer, such as we find it in the Summa Theologiae, is largely Thomas' own creation; although there were scholastic treatises on prayer before Thomas, they had done little to sort out either the structure or the content such a treatise needed. It is therefore a matter of considerable interest to see how Thomas progressively clarified his own ideas on the subject. The whole dossier would be beyond the scope of this volume, but I have included what seem to me to be the most important texts. For convenience, I list them here, with brief notes on their dating and on the state of the text.
(1)Scriptum super Libros Sententiarum IV, distinction 15, question 4. This is Thomas' earliest treatise on prayer, dating from about 1255-56. I have used the edition by M. F. Moos (Paris, 1947).
(2)De Veritate question 6, article 6. This question dates from 1256-57. I have used the Leonine edition, volume XXII.
(3)Contra Gentiles, book III, chapters 95-6. This dates from Thomas' time in Orvieto, in all probability, that is, about 1263. I have used the Leonine manual edition (Rome, 1934).
(4) Commentary on 1 Corinthians 14:13-15 and 1 Timothy 2:1. These lectures, in their final form, apparently date from Thomas' second Parisian regency, but it is not impossible that in essence they go back to the first regency. If they are dated to the second regency, they surely antedate the commentary on Matthew, which must belong to the academic year 1270-71, as we have seen. Thomas' doctrine on the benefits resulting from prayer seems to have matured between the lectures on 1 Corinthians and the Summa Theologiae, so it looks as if 1271-72 can be excluded (though admittedly this kind of criterion is far from certain). I have used R. Cai's Marietti edition (Turin, 1953).
(5) Commentary on John 16:23. The lectures on John certainly