About the name “Sasan”
The ancestry of Bahá‘u‘lláh reaches back to the dynasties of ancient Persia. One of the most meaningful lines of descent to students of the Bible comes from the marriage of King Cyrus of Persia to a woman named Rahab, who was a descendant of King David of Judah. Bahá’u’lláh’s relationship to this marriage is through their son, Sásán, the patriarchal ancestor of the Sásánian dynasty of Persian kings.
Hasan Balyuzí, the eminent historian of Bahá’u’lláh’s life, wrote: “It is to Yazdigird III, the last Sásánian monarch to occupy the throne of Irán, that the genealogy of Bahá’u’lláh can be traced…”
Balyuzí substantiated this statement that Bahá’u’lláh was a descendant of Sásániam kings by citing the results of the research of Mírzá Abd’l-Fadl, and eminent Bahá’í teacher and scholar:
“Mirza Abu’l-Fadl writes that he was, in the course of his investigation, particularly impressed by the fact that so severe and unsympathetic a critic of the Bahá’í Faith…as Ridá-Qulí Khan-i-Hidáyat…had admitted in (The Book of Ancestry), that the Núrís of Mázindarán are descended from Chosroes I, the renowned Sásánian monarch known as ‘Adil (The Just). And final confirmation came from Hají Mírzá Rida-Qulí, a half-brother of Bahá’u’lláh, who told Mírzá Abu’l-Fadl categorically, in answer to his query, that the Núrís possessed a genealogical table tracing their line back to Yazdigird the Sásánian.”
Among the genealogies published by the meticulous Muslim historian at-Tabarí in his comprehensive history of prophets and kings was that of the Sásánian dynasty of Persian kings. It traced their lineage back to Sásán the Great, son of the legendary Persian king, Bahman, and then further back to King Lohrásb, who lived shortly before the time of the Prophet Zoroaster:
“Firúz, son of Yazdigird, son of Bahrám, son of Yazdigird, son of Shápúr, son of Hormuz, son of Narsí, son of Bahrám, son of Hormuz, son of Shápur, son of Ardashír, son of Bábak, son of Sásán I, son of Bahman, son of Isfandiyar, son of Gushtásb, son of Lohrásb.” ~ from The Ancestry of Bahá’u’lláh, by Phil Turner, from The Greater Covenant in the Bible: A Study Guide

Aside from that which is a matter of record in Persian histories, it is stated in the Old Testament — established today, among all European peoples, as a sacred and canonical Text — that in the time of Cyrus, called in Iranian works Bahman son of Isfandiyar, the three hundred and sixty divisions of the Persian Empire extended from the inner confines of India and China to the farthermost reaches of Yemen and Ethiopia. (Abdu’l-Baha, The Secret of Divine Civilization, p. 7)

Elsewhere in his history, at-Tabarí spoke of the mother of Sásán. He described her as a descendant of the kings of Judah:
“The mother of Bahman’s son was the slave Rahab bint Pinchas, of the children of Rehoboam b. Solomon b. David. Bahman appointed Rahab’s brother Zerubabel b. Shealtiel king over the Israelites, transferred to him the office of the exilarch, and returned him to Palestine, upon Rahab’s request. Bahman died and left (the following) offspring: two sons, Darius the Great and Sásán, and daughters Khumani, who ruled after him, and Franik and Bahman Dukht.”
The circumstances of Zerubbabel’s appointment described above identify Bahman unmistakably. The Persian king who appointed Zerubabbel and ordered his return to Jerusalem was Cyrus the Great, according to chapters 1 and 2 of the book of Ezra. A Christian historian of a later period confirmed the veracity of at-Tabarí’s statement. Bar-Hebraeus (Arabic Ibn al-‘Ibrí), who became the assistant patriarch of the Eastern Jacobite Church in the city of Marágheh is Adhirbáyján in 1264 AD, left this record:
“Cyrus the Persian reigned thirty-one years, and conquered Iraq, Khurásán, Armenia, Syria and Palestine, and invaded India, killing their king. This Cyrus married the sister of Zerubbabel, son of Shealtiel, son of Jehoiachin, son of Jehoiakim, the king of Judah. And after he married her, she became highly esteemed in his sight, and he said to her, ‘Ask of me whatever you want,’ so she asked for the return of the children of Israel to Jerusalem and that he grant them permission to rebuild it…And because of the mixing of Cyrus with the offspring of David, Isaiah the prophet said of him before he was born, ‘God said to his anointed one, Cyrus, by whose right had I have been strengthened…”[See Isaiah 45:1]
~ from The Ancestry of Bahá’u’lláh, by Phil Turner, from The Greater Covenant in the Bible: A Study Guide

Psalm 89 : 34 - 36
34 My covenant will I not break, nor alter the thing that is gone out of my lips. 35 Once have I sworn by my holiness that I will not lie unto David. 36 His seed shall endure for ever, and his throne as the sun before me.

http://www.mb-soft.com/believe/txc/genealog.htm

Isaiah 44 : 24 - 28
24 Thus saith the LORD, thy redeemer, and he that formed thee from the womb, I [am] the LORD that maketh all [things]; that stretcheth forth the heavens alone; that spreadeth abroad the earth by myself; 25 That frustrateth the tokens of the liars, and maketh diviners mad; that turneth wise [men] backward, and maketh their knowledge foolish; 26 That confirmeth the word of his servant, and performeth the counsel of his messengers; that saith to Jerusalem, Thou shalt be inhabited; and to the cities of Judah, Ye shall be built, and I will raise up the decayed places thereof: 27 That saith to the deep, Be dry, and I will dry up thy rivers: 28 That saith of Cyrus, [He is] my shepherd, and shall perform all my pleasure: even saying to Jerusalem, Thou shalt be built; and to the temple, Thy foundation shall be laid.”

Isaiah 45 : 1
“1 ¶ Thus saith the LORD to his anointed, to Cyrus, whose right hand I have holden, to subdue nations before him; and I will loose the loins of kings, to open before him the two leaved gates; and the gates shall not be shut;