It is for gratifying our desires when those desires have been so purified and so saturated with God that they coincide with his plans. If we ask anything according to his will. In other words prayer is not for gratifying natural desires. Prayer is for satisfying the desires of people who are devoted to God's desires. Prayer is not for gratifying natural desires.
Prayer is for fruit-bearing.
The words of Jesus abiding in us prepare us for fruit-bearing prayer. The key to praying with power is to become the kind of persons who do not use God for our ends but are utterly devoted to being used for his ends. The words of Jesus abiding in us make us the kind of persons who are not dominated by natural desires, but are devoted to fruit-bearing for God's glory. Let me give you a few examples that show this from John's writings. The words of Jesus abiding in us is the key to a true and humble assessment of ourselves that keeps us in line with God's purposes.