So Old Jerusalem will be built up unto the house of Israel, and the New Jerusalem will be built up specifically unto the remnant of Joseph (and it will be built up only on “the principles of the law of the celestial kingdom”; D&C 105:5). Two of the most important signs of the times are the building of temples in Old Jerusalem and New Jerusalem, or Jackson County (Isaiah 2:2–3; Ether 13:8–12; D&C 84:2–4; 133:12–13). Speaking of Old Jerusalem, Joseph Smith said: “Judah must return, Jerusalem must be rebuilt, and the temple, and water come out from under the temple, and the waters of the Dead Sea be healed [see Ezekiel 47:1–9]. It will take some time to rebuild the walls of the city and the temple, etc.; and all this must be done before the Son of Man will make His appearance.”36