The prayers God answers are the prayers He originates.
"For Thou, O LORD of hosts, God of Israel, hast revealed to Thy servant, saying, I will build Thee an house: therefore hath Thy servant found in his heart to pray this prayer unto Thee" (II Samuel 7:27).
David "found in his heart" the leading and enabling of his Lord to pray in accordance with God's will. God illuminated David with the knowledge of His purposes concerning David's house and lineage, a heritage that would ultimately lead to the Lord Jesus Christ. "Christ cometh of the seed of David." David's prayer therefore began in Heaven, was faithfully assimilated and prayed upon the earth, and then returned to Heaven fragranced with the Divine and human elements that true prayer always involves (John 7:42).
We "ask amiss" when prayer originates not with God, but with the world, the flesh, and the devil. Doubtless billions of such prayers have been prayed in human history, and doubtless we have all participated in misguided offerings. Prayer is at once so simple that a child can perform the act, and so mysterious that no less than the Apostle Paul himself confessed, "we know not what to pray for as we ought." A good friend has suggested that one of the best things we can say to God as our prayer begins is the admission, "Lord, I don't know what I'm doing here!" We don't, and thus the Holy Spirit is required to lead and enable us to pray in a manner that satisfies both God's heart and our own. This makes prayer a matter of both relationship and Truth as we trust our Lord for His moving within our hearts, and we seek His Word in how to relate to God so we can have confidence that we are rightly responding to Him (Romans 8:26).
We wouldn't want it to be any other way. By definition, prayer is the act of acknowledging the greatness of God, and the weakness of humanity. "O Lord my God, Thou art very great... Lord, make me to know how frail I am." Whether we directly utter the words or not, our prayers must always be graced with the awareness of complete dependence on the Spirit of the Lord Jesus to work in us "both to will and to do of His good pleasure." He is the beginning and the ending, the Alpha and Omega of true prayer, and all glory is His when a trusting believer call us upon God, and God answers. "I can do all things through Christ which strengtheneth me" declared Paul. Nothing more requires the power of "through Christ" than prayer, and nothing more thrills our hearts than those times we can confess with David, "Thy servant hath within his heart to pray this prayer unto Thee" (Psalm 104:1; 39:4; Philippians 2:13; 4:13).
"Call unto Me, and I will answer Thee, and show Thee great and mighty things, which thou knowest not."