We began with an understanding that a Samaritan sect identified themselves with the Persian word 'friends' or dustan. We since moved on to the recognition that the same source - Hegesippus's Memoirs - identified another Samaritan group to venerate the Persian concept of Gorothmana - i.e. the highest of three heavens. As noted in one source:
If it appears that Paul is depending on the Persian construct of three heavens
Indeed the Marcionite tradition appears to have preserved the original Iranian understanding of the third heaven as a 'super heaven' above the realm of the material world where a wholly superior god lived.
In the later Persian text, the Life of Arda Viraf we see the continuation of the original interest in heavenly ascent:
Being the most pious of Mazda believers, Arda Viraf was chosen to go to heaven to bring back a revelation of Ormazd about the true religion. To induce ecstasy he is given a cup of narcotic to drink; whereupon he sinks into a deathlike sleep and lies in a fixed position for seven days, while his soul, conducted by Srosh and Atar, wanders through the heavenly regions. Crossing the Chinvad bridge, it traverses the place beneath the stars, where are the souls of those whose good and evil works balance each other, then crossing the three heavens,' arrives at Garothmana, the abode of Ormazd. Here it is shown the blessed place of the righteous souls and the damned place of the wicked spirits, whose joys and torments are described at length.
I tend to think that the ritualized context of secret Mark falls within the same context - that is, a seven day preparation period followed by a heavenly ascent.
Now to examine the meaning of Garothmana. It has long puzzled me how the Samaritans (and the Jews to a lesser extent) could have believed that mount Gerizim was a gateway to heaven given the fact that it doesn't at all resemble an impressive mountain. It is rather better described as a hill. The idea that a ladder extended up to heaven from this point is explained by the Samaritans themselves by claiming that the top of Gerizim disappeared and went up to heaven! This seems to imply that the religion adopted beliefs from somewhere else and adapted it to their rather unimpressive mound.
It would seem the Persian religion is the original source for this idea and specifically a mountain range that exists in north Iran on its border with the Caspian Sea. It is here for instance that Arda Viraf is said to have ascended up to Garothmana by means of a high mountain:
According to the Parsi belief, the good after death pass safely over the bridge Chinevat, which stretches from Mount Albori up to Garotman, the blissful realm of Urmuzd; while the wicked fall from the bridge into the Gulf of Duzahk, which yawns beneath, where they are tormented by d:evas. At the end of the world a comet will fall upon the earth, causing a vast conflagration, by which the whole earth will be melted, and the molten stream will pour down into Duzahk, carrying with it the sinners who are on earth at the time. Here they and the earlier comers, except those already redeemed by the prayers of friends, will burn for three days and nights, and then, thus purified, will be received into heaven. Afterward all the d.evas, and even the arch-fiend Ahriman, will have their evil burned away, and will also enter the abode of light.
As the Encyclopedia Iranica notes:
The most ancient layer of belief about the mythical “high Harā” appears to be that it was a huge mountain rising in the middle of the world, around whose peak (Av. taēra-, Pahl. tērag) “revolve the stars, moon, and sun” (Yt. 12.25), thus creating night and day. Each morning the “sun goes forth to cross high Harā in its flight” (Yt. 10.118); and Mithra, who goes before it, has his abode on the lofty, shining mountain, “where there is neither night nor darkness, neither cold wind nor hot . . . neither do mists rise from high Harā” (Yt. 10.50). Further, “just as light comes in from Harborz . . . water too comes in from Harborz” (Bd. 11.6); for the mythical river Arədvī Sūrā Anāhitā was held to pour down from the mountain’s peak into the ocean Vourukaša (Yt. 5.3; cf. Bd. 10.5-6), being thus the source of all the waters of the world. In Vendidad 21 an incantation links together light and the waters, high Harā and the ocean Vourukaša. In the yasna liturgy (Y. 42.3) the worshipers offer sacrifice to sky and earth, wind and the “Peak of Harā.” The peak is also called Mount Hukairya (Pahl. Hukar), “Of good activity” (Yt. 10.88); and worshipers of Arədvī Sūrā praise “Mount Hukairya the verdant, which deserves all praise” (Yt. 5.96), while in the Bundahišn “the lofty Hukar, through which springs the water of Ardvīsūr,” is called “the chief of summits” (Bd. 11.9; cf. Pahl.Rivayat 15.4).
The “abode and dwelling of the clouds” is on Harborz (Mēnōg ī xrad 44.16); and there the Baga set the sacred plant haoma to grow. There too the yazata Haoma, as priest of the gods, offers sacrifice, specifically to Mithra (Yt. 10.89) and to Sraoša (Y. 57.19). Figures of ancient Iranian myth, namely Haošyaŋha (Hōšang) and Yima (Jamšēd) are also said to have offered sacrifice on the mountain, to the divinities Arədvī Sūrā, Druvāspā, and Vayu (Yt. 5.21, 25; 9.3, 8; 15.7, 15).
Zoroastrian scholastics continued to suppose that the Peak of Harā intercepted the light of the heavenly bodies, which they thought had their orbits in planes parallel to the earth. The ancient Iranians used a 360-day calendar, and in Pahlavi texts (Bd. 56.3; Pahl. Rivāyat 65) it is said that there were 180 windows on the eastern side of the Peak, and 180 on the western side. Each morning the sun passed through one on the eastern side, and each evening it departed through one on the western side. There were likewise 135 windows on either side for the moon, and 90 for the stars; and Vanant, the “Conquering One,” chief star of the southern quarter, is said to be entrusted with guarding these apertures against demons, so that they may not block the passage of sun, moon, and stars (Mēnōg ī xrad 48.12-13). The addition of five extra days—the so-called “Gāthā” days—to the 360-day calendar at the first Sasanian calendar reform threatened the symmetry of this scheme, and the problem thus created could be regarded only as a mystery, as in the following gloss: “And on those five Gāthā days it [the sun] enters and leaves by the same window—a window which is not spoken of, for if it had been spoken of the demons would have known the secret, and harm would have been done” (Bd. 5b.4)
The Zoroastrian paradise is Garotman (Avestic garo dmana) where Ahura Mazda and the Amesa Spentas dwell, the highest of three levels. The paradise of the solar deity must have been current in the religious belief very early, perhaps the first or second c. A.D., since the sun god's paradise is called Heliloka, "Dwelling of the Sun", using Heli (Helios-Elios). Garodmana ("dwelling of the hymns")
Linguistically speaking we should see that the name for Heaven is Garo-de-mana (Garotman in Persian) 'house of hymns' because the angels are believed to sing hymns there (see Yas xxviii, 10; xxxiv, 2