Here is chapter 6 of the Life of St. Martin. In the previous excerpt, we saw Martin's encounter with robbers in the Alps and his conversion of one of his erstwhile captors. We find him now, in chapter 6, on his way to convert his parents and his people in Illyria.
When Martin left there and passed by Milan, the devil, taking up a human form, met him and asked him where he was going. When he received an answer from Martin that he was going where God called him, the devil said to Martin (2)"Wherever you go and whatever you should attempt, the devil will oppose you" Then, Martin answered him in a prophetic voice "The Lord is my helper. I will not fear what people do to me." Immediately, the enemy vanished from his sight. (3) Just as he intended, Martin released his mother from pagan error, although his father persevered in evil practices. Nevertheless, he saved many people by his example.
(4) Then, after the Arrian heresy had sprouted up throughout the whole world and, especially, in Illyria, and Martin, often alone, oppossed the treachery of the priests very bitterly and suffered many punishments--for he was beaten in public with rods and driven at last from the city, he headed for Italy. After he discovered the church was disturbed in Gaul also after the departure of Saint Hilary whom the power of the heretics drove into exile, he decided to establish a monastery near Milan. There, also, Auxentius, an author and leader of the Arrians, denounced heavily him, inflicted many injuries on him and drove him from the city. (5) Martin, thinking it was necessary to yield to the times, withdrew with one companion, a priest and a man of the greatest virtue, to an island whose name was Gallinaria. There he lived for some time on plant roots. At that time, he ate hellebore, a poison plant as they say. (6) But when he felt the force the poison advancing and death was near, he drove away the threatening danger with prayer and immediately all pain fled. (7) Not much later, whe he discovered that Saint Hilary was permited to return because the Emperor repented, he rushed to the city of Rome.
The first incident is a straight-foward encounter with the devil. Straight-foward, at least, in a hagiographical setting in which we can expect diabolical opposition against a saint and, of course, the saint's successful resistance against it. Martin's response to the devil is a simple affirmation of God as a helper; an affirmation which can be traced back to the Psalms and the OT in general.
The placement of this warning scene is also instructive. We find Martin on the cusp of a major missionary endeavor as well as becoming involved in a vicious international theological dispute (more on that later). In order to accomplish what he is trying to do, Martin will face exceptional resistance. The warning scene sets this expectation up and makes the spiritual stakes involved in the effort very clear.
The conversion of one's family is, of course, a hagiographical commonplace. If one is born from pagan parents, then, one can expect that a saint will convert them before too long. Here the conversion is incomplete, but, then, fathers do tend to resist Christianity more than mothers just as, I think men in antiquity resisted Christianity rather more than women. Just look at Augustine's father, who only converted in later life, after Augustine had been bishop for a time.
The main meat of this passage is Martin's anti-Arian efforts. Remember the period we are talking about. Until Constantius II emergence as the sole ruler of the Empire, efforts in 355, the Western churches had been generally pro-Nicene, although some Illyrian bishops had already shifted to the semi-Arian solution encouraged by Constantius. Once Constantius gained control in the West, the pressure was put on the West to conform to the official imperial religious position. The exile of St. Hilary and other Western leaders was merely one step in this effort. Martin's efforts have to be understood in that context.
It is, of course, striking that the saint's efforts fail pretty much without result. Martin fights Arianism vigourously, placing himself in areas dominated by the Arrians, but he is driven out in both cases. Given the intense pressure on the orthodox Nicenes at this time, we shouldn't be surprised. The heat was definately on as the Western Church was heading towards the Council of Ariminium in 359 which adopted a semi-Arrian, compromise creed under intense imperial pressure. The efforts of one monk was bound to be repulsed.
Yet, the pressure eases up at the end of this episode with news of St. Hilary's return from exile in 360. This return was odd, given Hilary's strong anti-Arrian sentiments. It is explained by suggesting that semi-Arrians wanted him to serve as an intermediary between them and the still Nicene hierarchy in the West or by the suggestion that the more radical Arrians were tired of being beaten in debates against Hilary. I suspect that, whatever the truth of either of these allegations (the first looking much more likely), Constantius was also calculating his advantages in the West in the light of the revolt of Julian in 360. Julian, while secretly a pagan, continued support of the Nicenes in so far as he involved himself in church politics. It was, thus, a helpful gesture to return a major Nicene leader from exile. Constantius certainly did this after Magnentius' revolt when he eased pressure on Nicene bishops in the East during hte civil wars. As soon as he gained full control in the West, he tightened the screws again. In all likelihood, he was planning to do the same thing before death overcame him in 361.