"If ... our emotional disturbance happens to be great, we will more surely keep our balance, provided we remember, and repeat to ourselves, a particular prayer or phrase that has appealed to us in our reading or meditation. Just saying it over and over will often enable us to clear a channel choked up with anger, fear, frustration, or misunderstanding, and permit us to return to the surest help of all—our search for God’s will, not our own, in the moment of stress." (Step Eleven, Twelve Steps and Twelve Traditions)
Repetitive prayer I find helpful, for the following purposes:
- Blocking unhelpful thinking
- Contemplating the ideas contained in the prayer
- Restoring me to a prayerful space
- Keeping me in a prayerful space
- Therefore remaining in awareness of the presence of God
- Invoking connection with all related prayers
- Invoking connection to all the other times I have prayed that prayer
- Invoking connection to all other people who pray that prayer
Petitionary prayer (prayer that asks for something) can be used in that way, but it is not because God needs to be nagged or harangued. If I repeat a petitionary prayer, the first iteration worked, and the rest are there for the other reasons listed above.
This is because God is principle, and God answers prayers. They do not need to be repeated for God to answer them.