The following comes from The Catholic Exchange:
Prayer is a powerful source of grace and the mother of all virtue but the Catechism acknowledges that prayer is a battle. The Gospel is the story of spousal love and prayer is a means of communicating that love. Love is a necessary catalyst for persevering in prayer.
A priest once relayed this story in a weekday homily: “When I was a newly ordained priest I was so happy and sure of the priestly authority of Jesus given to me through the sacrament of Holy Orders. Shortly after ordination I traveled to a famous Marian shrine to thank Our Lady for the helping me through the seminary. At the shrine several people asked me to aid a lady who was in spiritual distress and manifesting evil spirits. As I approached the woman I reminded myself that I have the authority of Jesus Christ and His Church to pray for her liberation. After ministering to her for a time I began to bind and cast evil spirits but nothing happened. I tried three times without results and a crowd was gathering. I began to doubt my ordination. The Lord spoke to my heart, “Look her in the eye and tell her that I, the Lord, love her. Let My love manifest through your priesthood.” When Father did as the Lord said, the evil spirit left with a loud scream, and peace was restored as everyone witnessed.
In each case of deliverance or exorcism we see the power of divine love evicting the evil one from the person and premises. The priest and team surround the afflicted person with the prayer of the Church wrapped in ardent charity.
Part four of the Catechism presents a section entitled, The Battle of Prayer:
2725. Prayer is both a gift of grace and a determined response on our part. It always presupposes effort. The great figures of prayer of the Old Covenant before Christ, as well as the Mother of God, the saints, and he himself, all teach us this: prayer is a battle. Against whom? Against ourselves and against the wiles of the temper who does all he can to turn man away from prayer, away from a union with God. We pray as we live, because we live as we pray. If we do not want to act habitually according to the Spirit of Christ, neither can we pray habitually in his name. The “spiritual battle” of the Christian’s new life is inseparable from the battle of prayer.
Prayer is absolutely transformative for good and that is why we have enemies of prayer that include our fallen nature, the flesh, the world and the devil.