In Matthew 6:7 Jesus teaches “do not heap up empty phrases” in prayer, some Protestants use this verse to criticize various Catholic forms of prayer which repeat phrases, such as litanies and the Rosary. However when the scripture is analyzed very well, it shows that Jesus’ focus is on the “vain,” and not on the “repetition.”
For example in Matthew 26:44, Jesus Christ prayed a third time in the garden of Gethsemane, saying the exact same words again. It is not the repetition that is the issue. It’s the vanity. God looks into our heart, not solely at our words.
Also, in Luke 18:13, the tax collector kept beating his breast and praying “God be merciful to me, a sinner.” This repetitive prayer was pleasing to God because it was offered with a sincere and repentant heart.
“And the four living creatures, each of them with six wings, are full of eyes all round and within, and day and night they never cease to sing, ‘Holy, holy, holy, is the Lord God Almighty, who was and is and is to come!’” (Revelation 4:8, RSV)
In Psalm 136, the phrase “For His steadfast love endures forever” is more repetitious than any Catholic prayer, and it is God’s divine Word.