The call to corporate prayer comes from Jesus Christ Himself. He tells us in Matthew 18:20 that wherever two or more are gathered in His name that He too will in fact be in the midst of them. In John 17:11 He asks the Father to keep the Body of Christ as one, as He and the Father are. He also shows us that Heaven moves, after God's people pray. Matt. 18:18-19 and 2 Chronicles 7:14: "If my people, who are called by my name, will humble themselves and pray and seek my face and turn from their wicked ways, then will I hear from heaven, and will forgive their sin and will heal their land."
We see in the Gospels how much time the Lord spent in prayer with the Father. We also see in the early church the gathering together for prayer, fellowship, and unity in the Body of Christ.
In all the relationships between God’s people, prayer is the reason for success. Prayer can defy all the power of the world and equip us to conquer that world for Christ.
Jesus spoke more about prayer than any preaching.