Which will come first: building the Temple or gathering in the exiles?

Building the Temple will come before the ingathering of the exiles. The Zohar proves this based on a verse in Psalms (147:2), “G-d rebuilds Jerusalem, and he will gather in the dispersed of Israel.” First G-d will build Jerusalem and only then gather in the exiles. Maimonides rules this way halachically—first Moshiach will rebuild the Temple and then all the Jews will be gathered to Israel.

This order of events corresponds to stages in G-d’s revelation in the time of Redemption. When G-d rebuilds the Temple He will dwell in it and be revealed in it. Later His light will shine throughout the world, which will lead to the Jewish people being gathered in and brought back to Jerusalem.

(Although today a significant proportion of the Jewish population lives in Israel, it is not equivalent to the ingathering of the people which will happen after Moshiach comes.)

At a later stage, the dead will be resurrected, and once again the Zohar brings evidence from Psalms. The verse quoted above (G-d will rebuild Jerusalem and gather in the dispersed) is immediately followed by the verse “He will heal the broken-hearted.” G-d will heal our broken hearts for the loss of all our loved ones and we will be reunited with them.

The Zohar also writes that the resurrection of the dead will take place 40 years after the ingathering of the exiles. However, the Lubavitcher Rebbe states that the Zohar is not a book of Jewish law and the years are not necessarily precise. According to Maimonides, it is possible that the resurrection will take place at the same time as the building of the Temple and the ingathering of the Jewish people.

In any event, the Zohar refers to the general resurrection of all Jewish people. Tzadikim, however, will be resurrected immediately as soon as Moshiach comes. The Ridbaz (Rabbi Dovid ben Zimra) points out in the name of the Ritva that there will be two stages in the resurrection: “First a private one for tzadikim who died in exile, which will be soon after Moshiach’s coming, and the tzadikim will merit to see the good of the Jewish people and the rebuilding of the Temple, and they will rejoice… The general resurrection will take place later, when we enter into Shabbat (the seventh millennium).

References: Zohar vol. I 134a, 139a, 140a. Bavli Brachot 49a. Sheilot u’Teshuvot Ridbaz vol. III ch. 244. Igrot Kodesh Rebbe Rashab vol. 1 letter 130. Mishneh Torah Hilchot Melachim 11:1-4. Hitvaaduyot 5750 Vol. 4 p. 105. Likutei Sichot vol. 28 p. 206.