Egyptian astrologers observed that the star Sirius always rose annually on the eastern horizon "70 days after the star had been seen for the last time on the western horizon at sunset (known as the Heliacal Setting)" NOTE.
The annual heliacal setting of Sirius was viewed by ancient Egyptians as symbolizing death. The 70 day period then represented a period of darkness preceding the reappearance—symbolizing rebirth—of Sirius in the eastern horizon. In ancient Egypt, the setting occurred on 04.16. (Today Sirius sets on 04.24.)
While this was viewed as the beginning of death and darkness by the Egyptians, the slightly earlier counterpart on the lunar cycle became, for Israelis, Firstmonth—the New Year and symbol of rebirth. Considering the difference between the Egyptian astral year and the Israeli lunar year,
Interestingly, the Egyptian association of the heliacal setting of Sirius (04.24) meaning, to them, 70 days of darkness and death, apparently coincided with the timing, and 10 plagues, preceding the
"The Pyramid Texts, however, as well as later funerary texts, make it clear that the ideal time and place of 'rebirth' [for Egyptians] was in the eastern horizon at the time of the so-called heliacal (dawn) rising [i.e., return] of the star Sirius (Sothis), the latter identified to Isis," NOTE the Dog Star or 'Nile Star." In ancient Egypt, this occurred on 06.25, the Egyptian New Year. (Today, the heliacal rising of Sirius occurs on 07.03.)
The orientation of the shafts in the pyramids was seen by the Egyptians to "provide a means for the dead [Pharaoh] to reach the circumpolar stars in the north [which appear every day without fail, seen as symbols of eternity], known as the 'Imperishables'. The stars that were most likely targeted were those of Ursa Major, known as the 'Bull's Thigh.'" NOTE This was believed to correspond with the annual "rebirth" rising of Sirius.
Number of family members who migrated to Egypt (Shᵊm•otꞋ 1.5; Dᵊvâr•imꞋ 10.22)
Rabbis have had difficulty counting and defending an approximate 70 family members into exactly 70 named members, which required a little fudging to get it exact. Perhaps this is because the number 70 may have been intended not as literal but, rather, to symbolize the beginning of a 400 actual-year period of death and darkness—"going down" from Israel into Egypt. This also opens the possibility that, including servants (some of whom may have comprised a small tribal army of servant-warriors), the actual number may have been significantly greater than 70. The entire Middle-East would likely have known of the Egyptian superpower's association of 70 with the "death and darkness" period of Sirius' 70-day absence.
Number of Zᵊqan•imꞋ appointed by Mosh•ëhꞋ to Beit-Din hâ-Jâ•dolꞋ (Shᵊm•otꞋ 24.9) and around OꞋ hë- Mo•eidꞋ (bᵊ-Mi•dᵊbarꞋ 11.24)
In the case of the 70 Zᵊqan•imꞋ whom Mosh•ëhꞋ appointed to the first Beit-Din hâ-Jâ•dolꞋ, this is one zâ•qeinꞋ to bring order and adjudicate Tor•âhꞋ for each of 70 (symbolic) days of death and darkness prophesied to last until the "birth" of hâ-o•lâmꞋ ha-bâꞋ.
Number of date-palms at Eil•imꞋ
Cited within the context of 12 springs, symbolizing the 12 tribes as wellsprings of "living water," 70 date-palms, symbolizing nourishment, represent the 70 Zᵊqan•imꞋ of the Beit-Din hâ-Jâ•dolꞋ bringing the Light of Tor•âhꞋ during the period of death and darkness.
Eschatological "Years" Subjugated Under the goy•imꞋ (Yi•rᵊmᵊyâhꞋu 25.11ff)
This is the period of death and darkness Christians have called "The Time of the Gentiles."
Number of "Weeks" of Dân•i•eilꞋ (9.24ff)
This is the same period of death and darkness cited by Yi•rᵊmᵊyâhꞋu above.
The Nᵊtzârim Reconstruction of Hebrew Matitᵊyâhu (NHM, in English) 18.22: "Yᵊho•shuꞋa said to him, 'I don’t tell you [to forgive your brother] only until seven times, but rather until seventy times seven.'"
RibꞋi Yᵊho•shuꞋa explicitly associates the perfect number, seven, with the number symbolizing the period of death and darkness (see NHM note 18.22.1) to imply that the seven—perfect—meaning of the Ha•lâkh•âhꞋ requires forgiving your brother throughout the 70—period of death and darkness—i.e., the "70 Years" of Yi•rᵊmᵊyâhꞋu and "70 Weeks" of Dân•i•eilꞋ.
70 also symbolizes the nations of the goy•imꞋ. Thus, the symbol of 70 is consistent throughout.
Numerology is also covered in pâ•râsh•otꞋ wa-Yei•tzeiꞋ, Ta•zᵊriꞋa and bᵊ-Ha•al•otᵊkhâꞋ.