1 The second proposition of Jovinianus is that the baptized cannot be tempted by the devil. And to escape the imputation of folly in saying this, he adds: “But if any are tempted, it only shows that they were baptized with water, not with the Spirit, as we read was the case with Simon Magus.” Hence it is that John says, “Whosoever is begotten of God does no sin, because his seed abides in him: and he cannot sin, because he is begotten of God. In this the children of God are manifest, and the children of the Devil.” And at the end of the Epistle, “Whosoever is begotten of God sins not; but his being begotten of God keeps him, and the evil one touches him not.”
Source: Against Jovinianus (New Advent)