The exodus of the Jewish people from Mitzrayim took place in the year 2448. But Chazal relate that it was preceded by another exodus that of the members of Shevet Ephraim which ended in tragedy.

In the Gemara’s discussion (Sanhedrin 92b) of the identities of the dead people whom Yechezkel HaNavi resurrected as described in Sefer Yechezkel Chapter 37 one of the opinions cited is the following: “Rav says that these were the children of Ephraim who calculated the end [of the exile in Mitzrayim] and erred as the pasuk [Divrei HaYamim I 7:20–21] states: ‘The sons of Ephraim were Shuselach and his son Bered and his son Tachas and his son Eladah and his son Tachas. And his son Zavad and his son Shuselach and Ezer and Elad and the people of Gas who lived in the land killed them because they came down to take their cattle.’ It says further (ibid.  pasuk 22) ‘Ephraim their father mourned them for many days and his brothers came to console him.”

Rashi (ibid. s.v. V’ta’u) explains the error that the members of Shevet Ephraim made. When Avraham was 70 years old Hashem told him at the Bris bein HaBesarim that his offspring would be “strangers in a land that is not theirs and they will enslave them and afflict them for 400 years.” Thirty years later when Avraham was 100 years old Yitzchak was born. Since Hashem promised Avraham that only Yitzchak would be considered his “offspring” (Bereishis 21:12) the 400 years of galus actually began with the birth of Yitzchak. But Bnei Ephraim erroneously concluded that the 400 year period began with the Bris bein HaBesarim itself. This miscalculation led them to leave Mitzrayim 30 years earlier than the Divinely ordained time of the Exodus.

Targum Yonasan on the pasuk “Hashem did not lead them through the land of the Pelishtim” (Shemos 13:17) cites the massacre of Bnei Ephraim as the reason (translation follows Keser Yonasan): “When Pharaoh sent out the people Hashem did not guide them through the land of the Pelishtim because it was nearby for Hashem said that the people might be frightened when they saw their brothers who had died in battle. Two hundred thousand soldiers from the tribe of Ephraim carrying shields and spears and weapons had gone down to Gas to plunder cattle from the Pelishtim and because they transgressed Hashem’s decree and left Mitzrayim 30 years before the end they were delivered into the hands of the Pelishtim who killed them. These were the dry bones that were resurrected by Hashem’s word through the Navi Yechezkel in the valley of Dura.[i] If they were to see them in that condition they would be frightened and return to Mitzrayim.”

The Midrash (Shemos Rabbah 20:11) adds a novel interpretation of this pasuk which is also based on the episode of Bnei Ephraim: “Hashem took the blood of Bnei Ephraim and immersed His vessels in it so to speak as the pasuk says (Yeshayahu 63:2) ‘Why is your raiment red?’ Hashem said: I will not be consoled until I exact vengeance for the children of Ephraim as the pasuk says ‘V’lo nacham Elokim.’ ” The straightforward translation of this pasuk is “Hashem did not lead them ” but it can also be read “Hashem was not consoled.”