When you pray, do not use vain repetitions as the heathen do. Matthew 6.7
Sometimes, when my daughter was younger, I hated taking her shopping. Not only did she always want something no matter where we were shopping (her favorite store is still Menard's, the hardware super-store), she was consistent, and persistent in her pleas for the desired item. After a while it became tempting to make the purchase just to get her to quit begging. I could only take her being on my nerves for so long.
Many people view prayer in the same way. We think that if we do not get what we want the first time, we should ask God again, and again, and again... Eventually we will wear down the Lord's defenses and give it to us, whether we should have it or not. So we pray. And pray. And pray. It is sometimes discouraging, but we count it as faithfulness.
This is not what God wants, however. Before you think that I am against faithfulness or persistence, hear this: Trust in God. He knows what you want. He knows what you need. And most importantly, he knows his will for your life. It is not easy, but we are called to offer our prayers to him, and trust that he will answer. It could be- and often is- that our repetitions in prayer are a sign that we know we are out of God's will, or that we do not have faith in his ability. Give your needs to God and let him take care of them.
PRAYER: It is hard for us to feel that we are not in control, Lord. We want you to act, and to act now. We feel like if we tell you, over and over, our chances are better. Forgive us those sins, Jesus. Fill us with faith to know that you are in charge and taking care of us. Amen.