Marinus of Samaria, The Life of Proclus 18-19
Proclus made use of the noble purificatory practices which woo us from evil, that is lustrations and all of the other processes of purification whether Orphic or Chaldean, such as dipping himself into the sea without hesitation every month, and sometimes even twice or thrice a month. He practiced this discipline, rude as it was, not only in his prime, but even also when he approached his life’s decline; and so he observed, without ever failing, these austere habits of which he had, so to speak, made himself a law … As to the necessary pleasures of food and drink, he made use of them with sobriety, for to him they were no more than a solace from his fatigues. He especially preached abstinence from animal food, but if a special ceremony compelled him to make use of it, he only tasted it, out of consideration and respect. Every month he sanctified himself according to the rites devoted to the Mother of the Gods by the Romans, and before them by the Phrygians; he observed the holy days observed among the Egyptians even more strictly than did they themselves; and especially he fasted on certain days, quite openly. During the first day of the lunar month he remained without food, without even having eaten the night before; and he likewise celebrated the New Moon in great solemnity, and with much sanctity. He regularly observed the great festivals of all peoples, so to speak, and the religious ceremonies peculiar to each people or country. Nor did he, like so many others, make this the pretext of a distraction, or of a debauch of food, but on the contrary they were occasions of prayer meetings that lasted all night, without sleep, with songs, hymns and similar devotions. Of this we see the proof in the composition of his hymns, which contain homage and praises not only of the Gods adored among the Greeks, but where you also see worship of the God Marnas of Gaza, Asklepios Leontukhos of Askalon, Thyandrites who is much worshipped among the Arabs, the Isis who has a temple at Philae, and indeed all other divinities. It was a phrase he much used, and that was very familiar to him, that a philosopher should watch over the salvation of not only a city, nor over the national customs of a few people, but that he should be the hierophant of the whole world in common. Such were the holy and purificatory exercises he practiced, in his austere manner of life.

Suidas s.v. Hêraïskos
Hence his life also reached such a point that his soul always resided in hidden sanctuaries as he practiced not only his native rites in Egypt but also those of other nations, wherever there was something left of these. Heraiskos became a Bakchos, as a dream designated him and he traveled widely, receiving many initiations. Heraiskos actually had a natural talent for distinguishing between religious statues that were animated and those that were not. For as soon as he looked at one his heart was struck by a sensation of the divine and he gave a start in his body and his soul, as though seized by the God. If he was not moved in such a fashion then the statue was soulless and had no share of divine inspiration. In this way he distinguished the secret statue of Aion which the Alexandrians worshiped as being possessed by the God, who was both Osiris and Adonis at the same time according to some mystical union. There was also something in Heraiskos’ nature that rejected defilements of nature. For instance, if he heard any unclean woman speaking, no matter where or how, he immediately got a headache, and this was taken as a sign that she was menstruating.

Suidas s.v. Sarapio
For Isidore said that never in fact could he persuade him to meet another man, especially because when he grew old he no longer came out frequently from his own house; he lived alone in a truly small dwelling, having embraced the solitary life, employing some of the neighbors only for the most necessary things. He said that Sarapio was exceptionally prayerful, and visited the holy places in the dress of an ordinary man, where the rule of the feast led him. For the most part he lived all day in his house, not the life of a man, but to speak simply, the life of a God, continually uttering prayers and miracle-stories to himself or to the divinity, or rather meditating on them in silence. Being a seeker of truth and by nature contemplative, he did not deign to spend time on the more technical aspects of philosophy, but absorbed himself in the more profound and inspired thoughts. For this reason Orpheus was almost the only book he possessed and read, in each of the questions which came to him always asking Isidore, who had achieved the summit of understanding in theology. He recognized Isidore alone as an intimate friend and received him in his house. And Isidore seemed to observe in him the Kronian life of mythology. For that man continued doing and saying nothing else but recollecting himself and raising himself, as far as he could, towards the inward and indivisible life. He despised money so much that he possessed nothing whatever but only two or three books (among these was the poetry of Orpheus); and he despised the pleasures of the body so much that straightway from the beginning he offered to the body only what is necessary and alone brings benefit, but of sexual activity he was pure throughout his life. And he was so little concerned about honor from men that not even his name was known in the city. He would not have been known subsequently, if some one of the Gods had not wished to make him an example for mankind of the Kronian life. He used Isidore as an heir, having no heir from his family, nor supposing that anyone else was worthy of his property, I mean the two or three books.