1. Because we know that God's word will not return void Isaiah 55:11 (KJV). God's word is powerful and our application of His word in prayer will produce results because the words are from God: they already contain His power.
2. Because we know that God's word is according to His will. These are not prayers that are easily twisted to our own desires or prayed with a false heart because the words confine us to a specific God approved desire and petition. The presence of the petitions in the word makes them God's express will and therefore our prayers will be according to His plan and purpose.
3. In the absence of knowing what to say, praying the scriptures guides our hearts towards proper desires and proper prayer. Even as we pray the scripture, we apply them to our heart and they begin to work in us molding our heart as we express our desire for the designs of God's word.
Some of the easiest scripture to pray is found in the epistles because the writers often document their prayers for the recipients. Many times I simply adapt these prayers to my own circumstances by switching the pronouns into first second or third person as it applies. I include below a list of scripture that I've used to pray in the past and some that I still use frequently, that can easily be adapted by simply switching the pronouns.
Some Scriptures to Pray:
1 Corinthians 1:4-8, Ephesians 1:15-23, Philippians 1:9-11, Colossians 1:9-14, 2 Thessalonians 1:11-12, Philemon 1:4-6, Hebrews 13:20-21, 1 Peter 5:10-11, Colossians 4:2-4, 2 Thessalonians 3:1-2
14For this reason I bow my knees before the Father, 15from whom every family in heaven and on earth is named, 16that according to the riches of his glory he may grant you to be strengthened with power through his Spirit in your inner being, 17 so that Christ may dwell in your hearts through faith—that you, being rooted and grounded in love, 18may have strength to comprehend with all the saints what is the breadth and length and height and depth, 19and to know the love of Christ that surpasses knowledge, that you may be filled with all the fullness of God.
14For this reason I bow my knees before YOU Father, 15from whom every family in heaven and on earth is named, 16that according to the riches of YOUR glory YOU may grant (INSERT NAME) to be strengthened with power through YOUR Spirit in (INSERT NAME) inner being, 17 so that Christ may dwell in (INSERT NAME) hearts through faith—that (INSERT NAME) , being rooted and grounded in love, 18may have strength to comprehend with all the saints what is the breadth and length and height and depth, 19and to know the love of Christ that surpasses knowledge, that (INSERT NAME) may be filled with all the fullness of God.
I additionally had a powerpoint file I made of these verses with the pronouns already altered, which we scrolled through during silent group prayer and we prayed through the scripture together . I've broken the powerpoint into image files and include them below. You can use them as desktop backgrounds or paste them into a powerpoint etc. for your own use. Just click on the image and it should give you the full size 1280 x 1024.
In addition to these prayers I turned Romans 6 into a prayer for my personal use. This was much more personalized and paraphrased, but I made it by going through verse by verse and restating it to God. Its a much freer prayer with the scripture at its root.
Romans 6 Prayer
O Lord, through Jesus Christ and His cross I have found favor in your sight, but though your grace and your love is unconditional, I must not remain in sin, Lord. I know that when Christ died as sin and to sin, I also died to sin and I know that I can’t live in sin any longer. In the name of the Lord Jesus Christ, I ask that you make this heavenly reality real in my life today. O Lord, I never want to step out of the fact that as I have been baptized into Christ, I have been baptized into His death. I want to know that I was buried with Christ by a baptism into death, so that just as Christ was raised from the dead by Your glorious power, so I also will always live and behave in newness of life. Father let me live in this newness of life today. Lord, Your word says that if we have become one with Him by sharing a death like His, we shall also be one with Him in sharing His resurrection. Don’t let me dodge the death of Christ today. I want to take up my cross today, so I can live in His resurrection for eternity. O Jesus, help me know, make it so real to me that my old self was nailed to the cross with You and I bear it no more, so that my body of sin would be made ineffective for evil, that I might no longer be a slave to sin. I know that if a man is dead, he is free from sin. I want to be that dead man today. Your word says that if we have died with Christ we shall also live with Him. O how I want to live with Christ. This is my prayer today. Show me the way to live with my Jesus. For I know that Jesus died once and for all and that death has no power over Him. He died once and when He did, He died to sin and it can never touch Him again. He lives to you alone Father. Your word tells me to consider myself dead to sin but alive to You in Jesus. I want this so much Lord. O Father don’t let this truth pass me by. I want to live in it. I want to live in it today Father. I don’t want sin to reign in my mortal body. I don’t want to be subject to its cravings and lusts and evil passions. O Lord I don’t ever want to offer or yield my body or its parts to sin. I don’t want them to be instruments of evil. I offer and yield them to You Father. You have raised me from the dead. Here is my body, use it as a tool of righteousness. Here are my hands, here are my feet, here are my eyes, here is my mouth. All to Jesus, all to Jesus all my being’s ransomed powers. For sin shall not exert dominion over me. I am not under the law but under grace. I will not sin, though I am always under Your favor. Lord, I know that I am a slave to whomever I surrender myself to obey. I don’t want to surrender myself to sin. I thank You Jesus, I thank You Father that though I was once a slave to sin, I have become obedient with all my heart, all my heart, (purify it Lord) to the teaching You have sent. I thank You that I have been set free from sin and become a servant of righteousness. Help me Lord, to always and today yield now my body and its parts as servants of righteousness to sanctification. Lord I was a slave to sin, marching towards death. Now, Lord I have been set free and I’m your slave in holiness to eternity. The wages of sin is death, but the gift you have given me is eternal life. Thank you, Lord that it is true in my life today. I take up my cross Lord, and I follow after You in this truth. Eternity starts now. Stamp it on my eyes, in Jesus name, Amen.
Going through scripture and turning it into prayers is a powerful way to interact with God's word. It directly applies the word to your heart and allows your desires to conform to what the Bible says. Reading the Bible with this intention and using it as a means of directing your communication with God can realign your relationship with Him and give you a new focus on the Bible as a living book that's practical, applicable and powerful as you see God answer the supplication you've prayed from scripture.