Now this is the confidence that we have in Him, that if we ask anything according to His will, He hears us.
1 John 5:14 (NKJV)
Many of us struggle with prayer because we don't understand the difference between knowing God's will and guessing God's will. This explains our unsettled feelings and concerns after praying because we are unsure whether or not our prayers were heard. The truth is that praying in accordance with God's will is not difficult if we learn to pray in the reality of the New Covenant.
What does it mean to pray in the New Covenant's reality?
It is to pray with confidence in the light of Christ’s finished work on the Cross.
All of God's will is found in the gospel of Jesus Christ—and the more we understand the gospel, the more our prayers will reflect the grace and truth of the gospel. In other words, it becomes increasingly difficult to believe that God will not answer your prayers when the gospel has already convinced you that He can and will.
A complete revelation of the gospel will change the way you pray, moving you from a struggling position of conflict and confusion about whether God will or will not hear you to a restful position of knowing you have all things in Christ. This is why the Apostle Paul prayed to God for spiritual wisdom and insight for every believer, so that we may truly grow in our understanding of our Father's love for us and fully possess the rich and great blessings God has promised us in Christ (cf. Ephesians 1:17-18).
The Apostle John tells we can have confident that God will hear our prayers
The Greek word for "confidence" is parrēsia which means "without ambiguity, boldness, cheerful courage" (Strong's G3954). This is what the early church prayed for when they were facing persecution (cf. Acts 4:29-31). They weren't looking for a rescue from God, but for God to embolden them with more grace to carry out His kingdom work on earth.
If you understand this revelation of praying in the reality of the New Covenant, it will change the texture of your prayer, from merely praying for our needs to proclaiming boldly the certainty of the finished work over life's challenges and circumstances.