Repetitive means to repeat over and over continuously,is this good for a christian.(1 Thessalonians 5:17) says,''pray continually.but Jesus also said ''But ye pray use not vain repetition as the heathen do,for they think that they shall be heard for their much speaking''(Matthew 6:7).The point Jesus was passing out here was that the repetition was vain or empty. Pagan or heathens do not have faith in God,so their prayers are empty or void of faith,the vain repetition Jesus was referring to was faithless repetition. People of faith often repeat what they believe.In (psalm 13:6) David continually repeated the same phrase.''His love(or mercies)endures forever''we repeat what we shall believe.(2 Corinthians4:13) says:''it is written:i believed,therefore i have spoken'' Jesus isn't concerned with repetition,his interest is in us having faith,in (Luke 18: He ask,when the son of man comes will he find faith on the earth.You can use repetition to grow your faith by praying in faith.