I'm not sure a pastor can overestimate the value of repeated words. You see we are so prone to doubt and forgetfulness, at least I am, that we need to hear things over and over again.
We understand this truth in some of the other contexts of life. It still moves my heart for my wife to tell me, "I love you," even though I have heard her say that literally thousands of times.
Our children hear us pray for them every night that "they would never know a day they did not love and trust the Lord Jesus as their Lord and Savior." (I learned this phrase by hearing it over and over again from my pastor during my years in seminary.)
A couple of weeks ago, when my small children were struggling a bit with all of the new things that have come with our move (home, school, routines, etc.), I told each of them at different times - "I have a job for you." I said, "I have an important job for you, do you think you can do it?" "Sure!" was the confident reply. I said, "Your job today is to remember that your Daddy loves you. Can you do that?" Each time a little face lit up, I received a nod or a "Yes," and I could see a precious soul encouraged. It's only been a couple of weeks, but now, as they are heading out to school, I just have to say - "Do you remember your job?" or "Remember your job today, okay?" and I see fresh encouragement. Repeated words are that powerful.
God himself filled the Bible with repeated words and phrases. "I will be your God, and you will be my people" is the refrain of God's love song to his people on page after page of Holy Scripture.
The Apostle Paul wrote, "It is no trouble for me to say the same things to you again, and it is a safeguard for you." (Philippians 3:1)
Repeated words are powerful. And the particular repeated words may change with a change in context, or perhaps over time, but it is hard for me to imagine pastoral ministry now without them.
Here are some of the repeated words I have heard myself saying over and over again:
(In pastoral conversation with someone struggling to believe that Jesus really takes away the guilt and the shame of sin)
"Listen to me. As a minister of the gospel, and on the authority of God's word, I tell you that your sins are forgiven because of Jesus."
(as a part of the liturgy of the Lord's Service)
-the Declaration of Forgiveness
"Almighty God, in his mercy, has given his Son to die for you, and for His sake forgives you of all of your sins. Therefore, upon your confession, I declare to you that God forgives you of all of your sins, in the name of the Father, and of the Son, and of the Holy Spirit. Amen."
-at the Lord's Table
"May our faith grow even now, so that we would believe more than ever before in the reality of our salvation - that our salvation is as real as the taste of this bread and the scent of this cup - for we pray in Jesus' name. Amen." (I also learned this phrase from Dr. George Robertson, my pastor during my seminary years, by hearing him use it so often.)
Don't people come to know what I'm going to say at certain times and in certain contexts? Yes. But they like it.
Can't repeated words, especially in a liturgy, become a lifeless routine? Yes. But abuse does not negate proper use. When the words of worship become a lifeless routine we must act pastorally and relationally - calling brothers and sisters to repentance and falling on our knees ourselves and praying that God would send again seasons of refreshing through the Savior appointed for us, even Jesus (Acts 3:19-20).