That quote is from R H Charles' Apocrypha & Pseudepigrapha of the Old Testament volume 2, the work being his ET of the Sibylline Oracles book 5 section 256-259, plus a bit from a second oracle that followed.
(256) Then there shall come from the sky a certain exalted man,
(257) whose hands they nailed upon the fruitful tree,
(258) the noblest of the Hebrews, who shall one day cause the sun to stand still,
(259) when he cries with fair speech and pure lips.
The footnotes say:
FWIW, Craig Evans' electronic Greek text (from J. Geffcken (ed.), Die Oracula Sibyllina (GCS 8; Leipzig: Hinrichs, 1902) as:256-9. A Christian interpolation.
257. MSS. 'whose hands he spread out', ... Fehr, ... renders ' whose hands the company of the Hebrews spread out '. Blass refers this line to Moses (Exod. xvii. 12). [RSV 12 But Moses' hands grew weary; so they took a stone and put it under him, and he sat upon it, and Aaron and Hur held up his hands, one on one side, and the other on the other side; so his hands were steady until the going down of the sun.]
258. In the MSS. the verb is in the past, ... Many commentators treat this as referring to Joshua [10:12-13], but manifestly the allusion is to St. Luke xxiii. 43, 44. [RSV: 43 And he said to him, "Truly, I say to you, today you will be with me in Paradise." 44 It was now about the sixth hour, and there was darkness over the whole land until the ninth hour. (personally, I do not think this is the "manifest," i.e., obvious, referent at all)]
which is very difficult to interpret and subject to many emendations by various scholars.256 εἷς δέ τις ἔσσεται αὖτις ἀπ᾽ αἰθέρος ἔξοχος ἀνήρ,
257 ὃς παλάμας ἥπλωσεν ἐπὶ ξύλου πολυκάρπου,
258 Ἑβραίων ὁ ἄριστος, ὃς ἠέλιόν ποτε στήσει
259 φωνήσας ῥήσει τε καλῇ καὶ χείλεσιν ἁγνοῖς.
Per J J Collins' translation of this passage in Charlesworth's The Old Testament Pseudepigrapha
Per the footnotes:(256) There will again be one exceptional man from the sky
(257) (who stretched out his hands on the fruitful wood)e3
(258) the best of the Hebrews, who will one day cause the sun to stand,
(259) speaking with fair speech and holy lips
A parallel is drawn to Lactantius Divine Institutions, bk 7.13:e3. At least this verse is Christian.
You can see clearly how this could relate to Joshua 10:12-13ANF vol 7 wrote:the impious king [i.e., the AntiChrist], inflamed with anger, will come with
a great army, and bringing up all his forces, will surround all the mountain in which the
righteous shall be situated, that he may seize them. But they, when they shall see themselves
to be shut in on all sides and besieged, will call upon God with a loud voice, and implore
the aid of heaven; and God shall hear them, and send from heaven a great king to rescue
and free them, and destroy all the wicked with fire and sword.
The rest of what you quoted is from the following unrelated oracle, which the footnotes say is about "The coming prosperity of Judaea and the plight of the ungodly."12 Then spoke Joshua to the LORD in the day when the LORD gave the Amorites over to the men of Israel; and he said in the sight of Israel, "Sun, stand thou still at Gibeon, and thou Moon in the valley of Aijalon." 13 And the sun stood still, and the moon stayed, until the nation took vengeance on their enemies.
You are reading a lot into this passage.Charles wrote:(260) Let thy spirit within thy breast no longer be vexed, thou blessed one,
(261) child of God, excellent in wealth, only longed-for blossom,
(262) pleasant light, august offshoot, longed-for branch,
(263) well-favoured Judaea, fair city, inspired in hymns.
(264) No longer shall the Greeks' unclean foot run riot in thy land,
(265) for they shall have within their breasts a mind that conforms to thy laws.
(266) But thy noble sons shall encircle thee with honour,
(267) and with holy music they shall attend thy table,
(268) with divers kinds of sacrifices and prayers to the honour of God.
(269) All those righteous men who from short-lived affliction have endured troubles,
(270) shall have a more ample and well-favoured rope of life.
(271) But the evil men who trim to the breeze a lawless tongue
(272) shall cease to speak one against another,
(273) and they shall hide themselves /until the world pass away/.
(274) And then shall come from the clouds a rain of flaming fire.
(275) No longer shall men gather in the blithe corn-blade from the earth.
(276) All shall remain unsown and unploughed, until mortal men take note of
(277) God, the Chief of all, the Immortal and Eternal,
(278) and no longer pay homage to mortal things,
(279) nor dogs and vultures, which Egypt has taught
(280) to reverence with vain mouths and foolish lips.
(281) But the holy land of the godly alone shall bear all these things.
(282) An ambrosial stream distilling honey and milk_shall flow from rock and fountain for all the righteous.
(284) For they fixed their hope on the one God, the Father who alone is excellent,
(285) and they held fast to great piety and faith.