Who will Build the 3rd Temple?

The 3rd Temple that will replace the 2nd Temple destroyed in Jerusalem will descend from heaven entirely built, according to sources (eg, Sukah 41a).

But how could this be; One of our 613 commandments explicitly states we must partake in building God's "House of Choice"? What then will it be, God-made or man-made?

The Rebbe, as he usually aligns what otherwise appear to be antithetical claims, explains: We have it from tradition the 3rd Temple will descend from heaven as a beautiful, finished building - except, its gates will be missing!

When the Babylonian enemy surrounded the 1st Temple, prior to destroying it, a miracle occurred and the earth swallowed the Temple's gates, as it says (Eicha 2:9), "Its gates sunk into the ground". These gates were built by King David (Sota 9a).

Says the Rebbe, to complete the 3rd Temple, Moshiach will "float" these gates up from the earth and, together with all the Jews, will install them into their proper places.

(As to how all Jews can participate in this event - the same way they all participated in the daily "Tamid" sacrifices - by way of 12 representatives, one from each tribe, being at location for the event, although here I surmise.)

You might think, "How trivial the task given the Jews" to install gates to the building. But think again; For a house without a door is as good as already broken into. This last task, of placing doors, is what secures the building, which now can fittingly be called - a house (בית), as in בית הבחירה or בית המקדש.