The Psalms have been known as a prayer book for thousands of years. They were part of the regular Jewish prayer life. These were prayers that Jesus himself prayed and yet, the psalms are about Jesus. All that the psalms are seeking God for, Jesus fulfills. This psalm specifically prays for the peace of Jerusalem and as we think about Jesus praying this very prayer, we know that he was going to become that peace that Jerusalem truly needs.
Image: TU REX GLORIAE CHRISTE, William Earley, photographed by Andreas F. Borchert (CC BY-SA 4.0). Image location: https://commons.wikimedia.org/wiki/File:Toomyvara_St._Joseph%27s_Church_Window_Tu_Rex_Gloriae_Christe_by_William_Earley_1933_2010_09_08.jpg