Matthew 26:44 Jesus prays in Gethsemane
So leaving them again, He went away and prayed for the third time, saying the same words.
There are more verses that talk about repeating prayer, the problem is vain repetitive prayer. The same goes for those who pray for ten minutes in prayer, using their own words and not truly believing them. It is not how many word you use or how much you repeat a word, it is when they are in vain that they are worthless.
I like to repeat this prayers from the heart:
For the sake of His sorrowful passion, have mercy on us and on the whole word.
or
Lord Jesus Christ, Son of the living God have mercy on me a sinner.
or
In the name of the Father, and of the Son and of the Holy Spirit. Amen!