What sermons of St Augustine are available in English translation?

The office of preaching belonged to bishops, and priests preached only with their permission. Even two such distinguished men as St. Augustine and St. Chrysostom preached, as priests, only when commissioned by their respective bishops. Origen as a layman expounded the Scriptures, but it was by special permission. But this is quite different from saying (as is stated by "Chambers' Encyclopædia", the "Encyclopædia Metropolitana", the "Encyclopædia Britannica", older edition) that priests were not ordinarily allowed to preach before the fifth century. This is not tenable in the light of history. For instance, Felix, priest and martyr, preached in the third century, under two bishops, Maximus and Quintus. Of the latter it was said that his mouth had the tongue of Felix (Thomassin, ibid., c. xiii, 505; Paulinus, "Poems"). Priests were forbidden to preach in Alexandria; but that was on account of the Arian heresy. A custom springing from this had spread to the north of Africa; but Valerius, Bishop of Hippo, broke through it, and had St. Augustine, as yet a priest, to preach before him, because he himself was unable to do so with facility in the Latin language -- "cum non satis expedite Latino sermone concionari posset". This was against the custom of the place, as Possidius relates; but Valerius justified his action by an appeal to the East -- "in orientalibus ecclesiis id ex more fieri sciens". Even during the time of the prohibition in Alexandria, priests, as we know from Socrates and Sozomen, interpreted the Scriptures publicly in Cæsarea, in Cappadocia, and in Cyprus, candles being lighted the while -- accensis lucernis. As soon as the Church received freedom under Constantine, preaching developed very much, at least in external form. Then for the first time, if, perhaps, we except St. Cyprian, the art of oratory was applied to preaching, especially by St. Gregory of Nazianzus, the most florid of Cappadocia's triumvirate of genius. He was already a trained orator, as were many of his hearers, and it is no wonder, as Otto Bardenhewer (Patrology, p. 290) expresses it, "he had to pay tribute to the taste of his own time which demanded a florid and grandiloquent style". But, at the same time, he condemned those preachers who used the eloquence and pronunciation of the theatre. The most notable preachers of the century, St. Basil and the two Gregories (the "Clover-leaf of Cappadocia"), Sts. Chrysostom, Ambrose, Augustine and Hilary, were all noted orators. Of the number the greatest was St. Chrysostom, the greatest since St. Paul, nor has he been since equalled. Even Gibbon, while not doing him justice, had to praise him; and his teacher of rhetoric, Libanius, is said to have intended John as his successor, "if the Christians had not taken him". It is a mistake, however, to imagine that they preached only oratorical sermons. Quite the contrary; St. Chrysostom's homilies were models of simplicity, and he frequently interrupted his discourse to put questions in order to make sure that he was understood; while St. Augustine's motto was that he humbled himself that Christ might be exalted. In passing we might refer to a strange feature of the time, the applause with which a preacher was greeted. St. Chrysostom especially had to make frequent appeals to his hearers to keep quiet. Bishops commonly preached outside their own dioceses, especially in the great cities; polished sermons were evidently in demand, and a stipend was given, for we read that two Asiatic bishops, Antiochus and Severianus, went to Constantinople to preach, being more desirous of money than of the spiritual welfare of their hearers (Thomassin, ibid., ix, 504).