Prayer Following a Pattern
In the Old Testament there is a large God-inspired prayer book — the Psalter. It was written by the prophet and king David. It was used at the temple; the psalms were sung while going up the steps.
When the apostles ask the Lord to teach them to pray, they refer to the fact that the prophet John the Baptist had already taught his disciples to pray:
“Now it came to pass, as He was praying in a certain place, when He ceased, that one of His disciples said to Him, ‘Lord, teach us to pray, as John also taught his disciples’” (Luke. 11:1)
After which Christ gave a pattern of prayer in His own words:
“So He said to them, ‘When you pray, say: Our Father in heaven, hallowed be Your name. Your kingdom come. Your will be done on earth as it is in heaven. Give us day by day our daily bread. And forgive us our sins, for we also forgive everyone who is indebted to us. And do not lead us into temptation, but deliver us from the evil one’” (Luke. 11:2-4) (Matt. 6:9-13)
That is, to give prayers and to pray following a pattern (a rule) is completely normal and is a biblical practice.