Augustine on Assurance of Salvation
Catholics believe in the existence of the Elect whose salvations are assured. The Elect are those whom God predestines to salvation since the initiative of our salvation belongs to God. However, unless God reveals it to us, we cannot know how many and who they are. Some Protestants and “Bible only” Christians, on the other hand, believe that once they believe in Christ as Lord and personal Saviour then they belong to the Elect and therefore have assurance of salvation.
We look at what Augustine wrote on this issue. The title of chapter 40 of one of his works, A Treatise on Rebuke and Grace, is “No One is Certain and Secure of His Own Predestination and Salvation”, in which he wrote (English Translation from Nicene and Post Nicene Fathers or NPNF Series I Volume 5, available online at http://www.ccel.org):
But, moreover, that such things as these are so spoken to saints who will persevere, as if it were reckoned uncertain whether they will persevere, is a reason that they ought not otherwise to hear these things, since it is well for them “not to be high-minded, but to fear” [Romans 11:20]. For who of the multitude of believers can presume, so long as he is living in this mortal state, that he is in the number of the predestinated? Because it is necessary that in this condition that should be kept hidden; since here we have to beware so much of pride, that even so great an apostle was buffetted by a messenger of Satan, lest he should be lifted up [2 Corinthians 12:7]. Hence it was said to the apostles, “If ye abide in me [John 15:7]” and this He said who knew for a certainty that they would abide; and through the prophet, “If ye shall be willing, and will hear me,” [Isaiah 1:19] although He knew in whom He would work to will also. And many similar things are said. For on account of the usefulness of this secrecy, lest, perchance, any one should be lifted up, but that all, even although they are running well, should fear, in that it is not known who may attain,-on account of the usefulness of this secrecy, it must be believed that some of the children of perdition, who have not received the gift of perseverance to the end, begin to live in the faith which worketh by love, and live for some time faithfully and righteously, and afterwards fall away, and are not taken away from this life before this happens to them. If this had happened to none of these, men would have that very wholesome fear, by which the sin of presumption is kept down, only so long as until they should attain to the grace of Christ by which to live piously, and afterwards would for time to come be secure that they would never fall away from Him. And such presumption in this condition of trials is not fitting, where there is so great weakness, that security may engender pride. Finally, this also shall be the case; but it shall be at that time, in men also as it already is in the angels, when there cannot be any pride. Therefore the number of the saints, by God’s grace predestinated to God’s kingdom, with the gift of perseverance to the end bestowed on them, shall be guided thither in its completeness, and there shall be at length without end preserved in its fullest completeness, most blessed, the mercy of their Saviour still cleaving to them, whether in their conversion, in their conflict, or in their crown!
Augustine, A Treatise on Rebuke and Grace, Chapter 40