What is the significance of "va'Yhi bi'Ymei"?
Ba'al ha'Turim (based on Megilah 10b, Tanchuma Shemini Atzeres 9): This occurs five times (the others are "va'Yhi bi'Ymei Amrafel" (Bereishis 14:1), "va'Yhi bi'Ymei Achaz" (Yeshayah 7:1), "va'Yhi bi'Ymei" Shefot ha'Shoftim" (Rus 1:1) and "va'Yhi bi'Ymei Achashverosh" (Esther 1:1).) It is an expression of Vai (pain).
Why does it say that this was in the days of Yoshiyah (verse 2), Yehoyakim and Tzidkiyah, until the exile?
Rashi: He prophesized all the remaining year s of Yoshiyah, the entire reign of Yehoyakim, and of Tzidkiyah, until the exile in Tzidkiyah's 11th year [like it says in Melachim II, 25:2 - Radak]. .
Malbim: This teaches when he prophesized. It was at three times, in which the situation of the nation and kingdom changed. He began in Yoshiyah ha'Melech's 13th year, when the king and the nation were Tzadikim. He continued in Yehoyakim's reign - the generation were Tzadikim, but the king was evil, like Chazal said (Sanhedrin 103a). He finished in Tzidkiyah's reign - the generation was evil, but the king was a Tzadik. At the time of the exile, all his prophecies were fulfilled.
