"Whatever you ask in My name, that will I do, so that the Father may be glorified in the Son." John 14:13
As God's representatives, it is our job to represent Him in the affairs of this world. To do that, we need to know what He wants, and have confidence that God will back us up as His legitimate ambassadors.
What God Wants
That's where God's Word comes in. Through it, we can know what God wants. "It's God's will that none should perish..." This gives us confidence in praying for those who do not yet know Him. As we remind God of His heart for the lost, and apply this scripture to a specific person, it gives us a solid place to stand. It strengthens our faith, that God will listen to our prayer and answer us, because it's the very thing that He already desires to do.
On God's Side
Praying God's Word puts us clearly on God's side, and gives us the courage we need to stand against the Devil and his schemes. Like an eviction notice from a judge, it gives us something of substance to press in upon the claims of the enemy. "To execute on them the judgment written; This is an honor for all His godly ones. Praise the LORD!" Psalm 148:9 The Devil might be able to bluff us into submission, but he cannot stand against God's Word. (see Matthew 3:1-11)
With Great Boldness
God's Word tells us that we can come boldly before His throne of grace. When we come with His word in our hand, we can require justice for the poor, healing for the sick, judgment for the wicked, and salvation for the lost. Whatever He has declared in His Word as a promise or as His desire, becomes for us the bold words of a child reminding his father of the promise he has made. "And now, O God of Israel, let your word that you promised your servant David my father come true." 1Kings 8:26.
It allows us to move beyond mere requesting. Just as a child might seem impertinent in demanding his father keep his promise, we can come to our heavenly Father with His own Word and require Him to honor it. This boldness is not irreverence, but an expression of our confidence in God's character. Moses, Abraham, Job, and Jacob, are examples of men who have reasoned and even argued with God, because they new His heart and believed in His character. "Come now, and let us reason together," Says the LORD..." Isaiah 1:18
Applying the Word
God's written Word gives us a general understanding of what He wants, but we need specific guidance to apply His Word effectively. As you begin to pray the scriptures over a certain need, ask the Holy Spirit to lead you, and look for Him to highlight one or more scriptures that you can focus on. As God quickens a particular scripture to you, use it as the weapon of choice for this battle. Grab hold of it and let your faith soar until there is no doubt in your heart. Cling to it, and proclaim it again and again, like a hammer hitting a small crack in a huge rock, until at last the rock splits. "But you, dear friends, build yourselves up in your most holy faith and pray in the Holy Spirit." Jude 1:20
End Result
Some needs must be hammered at in prayer for a long time. Some bust open with the first or second blow. You will know in your spirit when the job is done. This victory in the spiritual realm often comes before we see the reality in this physical realm. Don't trust what you see, trust what God says, and what His Spirit shows you.
Once you have "prayed through" to victory, then worship and thank God for the answer. Don't slip into unbelief just because you haven't seen the results yet. Results will come, if you stand in faith. Remember, God spoke the universe into existence, there is nothing more real, or more powerful than His Word. "I will bow down towards your holy temple and will praise your name... for you have exalted above all things your name and your word." Psalm 138:2
***From: http://prayitsayit.net. Visit this site for prayer requests and more on prayer.
