In addition to the two ways mentioned above, we also can limit God through ineffectual prayer. James 5:16b says, "The effectual fervent prayer of a righteous man availeth much." If this is true, then the opposite must also be true; ineffectual prayer availeth little. So how can we know that our prayers are making a difference? I would like us to take a look at three words in this verse.
First, lets look at the word "effectual." According to this dictionary, the word "effectual" means, "Producing an effect, or the effect desired or intended; or having adequate power or force to produce the effect. The means employed were effectual." How can we know that our prayers will have enough power to be effectual? First, let me explain something about how prayer works. As humans, we have all sinned, and thus cannot approach God. However, I John 2:1b says, "And if any man sin, we have an advocate with the Father, Jesus Christ the righteous:" Jesus is our advocate, meaning that Jesus approaches God for us. Thus, Jesus is the one who gives power to our prayers, so our prayers won't be effectual unless we are connected to Jesus. This brings us to the second word, "righteous."
According to the same dictionary , the word "righteous" means, "Just; accordant to the divine law. Applied to persons, it denotes one who is holy in heart, and observant of the divine commands in practice; as a righteous man." If we are not living righteous lives, we cannot be having fellowship with Jesus, and therefore our prayers won't make much difference. Now, by "righteous lives," I don't mean that we will never sin. Everyone sins, but Proverbs 24:16a says, "For a just man falleth seven times, and riseth up again." When a righteous man sins, he doesn't give up; he gets up and keeps going!
Lastly, lets look at the meaning of the word "fervent." According to the same source, the word "fervent" means, "to be hot, to boil, to glow." Are you hot, or just lukewarm? Fervency has nothing to do with how loud you pray with your mouth, but rather how loud you pray with your heart. In other words, a fervent prayer isn't measured by the tone of the mouth, but by the temperature of the heart. The more a person wants his prayer to be answered, the more fervently he will pray. If you find yourself indifferent as to whether or not your prayers are answered, ask God to change your heart and make you passionate about the things that He is passionate about.
In summary, if you are connected to Jesus, you will live righteously, which will lead to effectual prayers. And when you are in fellowship with the Maker of the universe, your spiritual temperature will rise, leading to fervent prayers. When these things happen, God's un-limited power is suddenly unleashed!