Jerusalem is central to the Jewish heart. When religious Jews pray three times a day, they always turn toward the Holy City. Synagogues likewise place the holy ark (the place where Torah scrolls are kept) on the wall closest to Jerusalem. Many observant Jews keep small section of an eastern wall of their house unpainted as a sign of mourning for the destruction of the Temple. Every year we close the Passover Seder with the words La-Shanah Haba'ah Bi Yerushalayim! ("Next year in Jerusalem"). These same words are invoked to conclude the holiest day of the Jewish year, Yom Kippur.
Yeshua called Jerusalem the "City of the great King" (Psalm 48:2; Matt 5:35). It is the place where He was crucified, buried, resurrected, and from where He ascended to heaven. It is also the birthplace of the church and the focal point of humanity's eschatological future. At the Second Coming, Yeshua will physically return to Jerusalem to restore the throne of King David. Then all the New Covenant promises given to Israel will be fulfilled as the Kingdom of God is manifest upon the earth.
In our verse, notice that the phrase "sha'alu shelom Yerushalayim" reveals prophetic truth about our Savior and Messiah. The word sha'alu means "you ask" (as in ask a sheilah, a question), shalom is the name of Yeshua, the Prince of Peace (Sar Shalom), and Jerusalem means "the teaching of peace" (Jeru- comes from the same root as the word Torah, which means "teaching"). The phrase sha'alu shelom Yerushalayim can be construed, "ask about the Prince of Peace and His Teaching." Yeshua is indeed the rightful King of Jerusalem who is coming soon to reign over all the earth.
Friends, let us never forget Zion, "the city of the living God, the heavenly Jerusalem" (Heb. 12:22). She is "our mother" (Gal. 4:26) and we are her citizens – even if we are still exiles in this present age. As the psalmist said, "If I forget you, O Jerusalem, let my right hand wither! Let my tongue stick to the roof of my mouth, if I do not remember you, if I do not set Jerusalem above my highest joy!" (Psalm 137:5-6). Let us "ask about the Prince of Peace and His teaching" and "badger" the LORD until He returns to make Zion "the praise of the earth" (Isa. 62:7).