Prayer and worship change the spiritual atmosphere of a region. In the Word of God and throughout history this has been proven over and over again.
In Luke 18:7, Jesus says, "And shall God not avenge His own elect who cry out day and night to Him, though He bears long with them?" Isaiah 62:6-7 says, "I have set watchmen on your walls, O Jerusalem; they shall never hold their peace day or night. You who make mention of the LORD, do not keep silent, and give Him no rest till He establishes and till He makes Jerusalem a praise in the earth."
God will establish his kingdom on earth through worship and prayer.