The second, a complete sentence, is found only once in Scripture. Psalm 122:6 says, "Pray for the peace of Jerusalem: they shall prosper that love thee." The Psalm, attributed to David, is known as a Psalm of Ascent; that is, a "song of Israel" that was "sung" as the Jews ascended up to Jerusalem for the Feast of Passover. Although only the first part of the verse is quoted, it is the second part of the verse that has made this statement very popular today among the "prosperity gospel folks." It has become sort of a "good luck" motto of those focusing upon themselves.
Unfortunately, those who say we are to pray for the peace of Jerusalem do not realize the ramifications of that prayer. First, the admonishment to pray for the peace of Jerusalem was written specifically to the Jews of David's day, and it is still the heart's desire of Jews today. Although they have possessed the city ever since the 1967 War, everyone knows that Jerusalem is far from being a city described as peaceful!
Students of Bible Prophecy know there are two major events that must occur prior to Jerusalem finding peace: the first is the Jews being deceived by the Antichrist, who offers them a seven-year "peace guarantee" (Dan. 9:27a; Mt. 24:1-14; Rev. 6 - 12), and the second is his breaking the "treaty" by committing the Abomination of Desolation and the Jews spending the next three and a half years "on the run" (Dan. 9:27b; Mt. 24:15-29; Rev. 13 - 18)! Genuine peace for the City will not occur until after the Second Coming of Christ and the Judgment of the Nations (Mt. 24:29 - 25:46; Rev. 19:11 - 20:15). Following the establishment of true peace, the old Jerusalem, and the whole world for that matter, is replaced with the "new heaven and a new earth" (Rev. 21:1 - 22:5).
So, when a born again believer prays for the peace of Jerusalem, he is actually asking that the Tribulation (a.k.a. Daniel's Seventieth Week - Dan. 9:24-27, and "the time of Jacob's trouble - Jer. 30:1-7) begin. The Bible makes the comparison of someone praying for the birth of a child without considering the agony and suffering of the mother during delivery (Gen. 3:16; Isa. 21:3; Jer. 30:6; Mic. 4:9; 1 Thes. 5:3; etc.).
Praying for the peace of Jerusalem is a prayer for Christ's Second Coming!
The first is preceded by much pain for the Jews!
The second is followed by much pain for the lost!