Repetition of Prayers

Pope leo explaining the rosary:

https://www.youtube.com/watch?v=rDu2vq8C4FA

Mathew 6:5-8

5 “And when you pray, do not be like the hypocrites, for they love to pray standing in the synagogues and on the street corners to be seen by others.
7 “And when you pray, do not use meaningless repetition as the Gentiles do, for they think they will be heard because of their many words. 8 So do not be like them [praying as they do]; for your Father knows what you need before you ask Him.

Besides the context of Jesus saying it's wrong to repeat prayer to be seen by others, the key phrase is “vain” (Greek: battalogein), which means “babbling,” “empty chatter,” or speaking without meaning or understanding.
Catholics argue Jesus was condemning mindless or superstitious recitation — not sincere, meditative repetition.

Catholic teaching emphasizes that the Rosary is not about “many words”, but about meditating on the life, death, and resurrection of Christ through a rhythm of prayer.

Prayer is a weapon against falling into sin.

Prayer repetition is to keep Gods word in our mind continually so our minds dont drift into sin. There is a difference between continually asking god for money or other vain repetitions, compared to the spiritual training exercise of discipline keeping your mind focused on holiness and reflecting on the word to make it second nature to you. The same with all practices in life. It's about keeping your minds continually focused on God in worship and depending on his Grace in prayer, rather than repetitive prayer requests.

“Meditation engages thought, imagination, emotion, and desire... The Rosary is a most excellent form of meditative prayer.” — Catechism of the Catholic Church, §2708

We don't have to fight for God's attention he's fighting for ours. Jesus repeated prayers of Psalms and in the garden asking the cup:

Matthew 26:44

So he left them and went away once more and prayed the third time, saying the same thing.

The author of Psalm 119 asks God repetitively to store up the law in his heart and to help him walk in the Lords precepts.

Psalm 119:164

Seven times a day I praise you for your righteous rules.

Psalm 136 is a good example of keeping your mind on God

1 Give thanks to the Lord, for he is good. His love endures forever. 2 Give thanks to the God of gods. His love endures forever. 3 Give thanks to the Lord of lords: His love endures forever.

Luke 18

The Parable of the Persistent Widow

1 Then Jesus told his disciples a parable to show them that they should always pray and not give up. 7 And will not God bring about justice for his chosen ones, who cry out to him day and night?

Ephesians 6:18

Never stop praying, especially for others. Always pray by the power of the Spirit. Stay alert and keep praying for God's people.

Romans 12:12

Rejoice in hope, be patient in tribulation, be constant in prayer.

1 Thessalonians 5:17

17 pray without ceasing

Colossians 1:3

We give thanks to God and the Father of our Lord Jesus Christ, praying always for you.

Colossians 4:2

Continue steadfastly in prayer, being watchful in it with thanksgiving.

Luke 18:1

And he told them a parable to the effect that they ought always to pray and not lose heart.

Luke 21:36

But stay awake at all times, praying that you may have strength to escape all these things that are going to take place, and to stand before the Son of Man.

Ephesians 6:18

Praying at all times in the Spirit, with all prayer and supplication. To that end, keep alert with all perseverance, making supplication for all the saints.

1 Chronicles 16:11

Seek the Lord and his strength; seek his presence continually.

2 Timothy 1:3

I thank God, whom I serve from my forefathers with pure conscience, that without ceasing I have remembrance of thee in my prayers night and day.

Daniel 6:10

He went to his house where he had windows in his upper chamber open toward Jerusalem. He got down on his knees three times a day and prayed and gave thanks before his God, as he had done previously.

Psalm 34:1

I will bless the Lord at all times; his praise shall continually be in my mouth.

Psalm 55:17

Evening and morning and at noon I utter my complaint and moan, and he hears my voice.

Psalm 71:8

My mouth is filled with your praise, and with your glory all the day.

Psalm 105:4

Seek the Lord, and his strength: seek his face evermore.

Psalm113

3 From the Rising of the sun to its setting, the name of the lord is to be praised!

Psalm 116:2

Because he inclined his ear to me, therefore I will call on him as long as I live.

Hebrews 13:15

Through him then let us continually offer up a sacrifice of praise to God, that is, the fruit of lips that acknowledge his name.

Malachi 1:11
11 For from the rising of the sun even to the going down, my name is great among the Gentiles, and in every place there is sacrifice, and there is offered to my name a clean oblation: for my name is great among the Gentiles, saith the Lord of hosts.

Romans 1:9

For God is my witness, whom I serve with my spirit in the gospel of his Son, that without ceasing I mention you always in my prayers.

Philippians 4:8
8 Finally, believers, whatever is true, whatever is honorable and worthy of respect, whatever is right and confirmed by God’s word, whatever is pure and wholesome, whatever is lovely and brings peace, whatever is admirable and of good repute; if there is any excellence, if there is anything worthy of praise, think continually on these things [center your mind on them, and implant them in your heart].

John 15:3
3 You are already clean because of the word I have spoken to you. 4 Remain in me, as I also remain in you. No branch can bear fruit by itself; it must remain in the vine. Neither can you bear fruit unless you remain in me.

Romans 12:1-2
A Living Sacrifice
12 I appeal to you therefore, brothers, by the mercies of God, to present your bodies as a living sacrifice, holy and acceptable to God, which is your spiritual worship. 2 Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect.

Psalm 119:9-16
9 How can a young man keep his way pure?
By guarding it according to your word.
10 With my whole heart I seek you;
let me not wander from your commandments!
11 I have stored up your word in my heart,
that I might not sin against you.

Psalm 1-20
The Way of the Righteous and the Wicked
1 Blessed is the man
who walks not in the counsel of the wicked,
nor stands in the way of sinners,
nor sits in the seat of scoffers;
2 but his delight is in the law of the Lord,
and on his law he meditates day and night.
He is like a tree
planted by streams of water
that yields its fruit in its season,
and its leaf does not wither.
In all that he does, he prospers.

Philippians 2
16 hold firmly to the word of life.

Revelation 4:8
8 Each of the four living creatures had six wings and was covered with eyes all around, even under its wings. Day and night they never stop saying:
“‘Holy, holy, holy
is the Lord God Almighty,’
who was, and is, and is to come.”

1 Corinthians 9:24-27
24 Do you not know that in a race all the runners run, but only one gets the prize? Run in such a way as to get the prize. 25 Everyone who competes in the games goes into strict training. They do it to get a crown that will not last, but we do it to get a crown that will last forever. 26 Therefore I do not run like someone running aimlessly; I do not fight like a boxer beating the air. 27 No, I strike a blow to my body and make it my slave so that after I have preached to others, I myself will not be disqualified for the prize.

Church Fathers:

Augustine

“God could have bestowed His gifts on us without our prayers, but He wished that by our prayers we should be made worthy to receive what He gives.”
— Letter 130

St. Louis de Montfort

“When we say to Mary, pray for us, we mean, ‘Join your prayers to ours.’ She prays only in and through Jesus Christ.”
— True Devotion to Mary, §85

Pope St. John Paul II

“Mary’s maternal role towards humanity in no way obscures or diminishes the unique mediation of Christ, but rather draws attention to it and illustrates it.”
— RM §38