At one point in my practice of our Byzantine traditions I remember a question that someone asked. They wanted to know if our traditions concerning the Jesus Prayer went against the Lord's teachings. The teaching that they were speaking of are in the gospel of Matthew where the Lord says, "When you pray, don't babble on and on as people of other religions do. They think their prayers are answered merely by repeating their words again and again (6:7,NLT).The question that was asked was reasonable based on this passage but this teaching does not represent the way the Jesus Prayer is used in our tradition. What the Lord was addressing was abusive forms of prayer, which in this case meant people who were not addressing God in personal way.
There are various ways that our Byzantine spiritual fathers have taught us to pray the Jesus Prayer. Among the teachings of our fathers there is nothing close to what can be considered vain repetition. The fathers were always clear that the goal of prayer is a personal relationship. Anything short of this is vain. For example, Elder Sophrony on addressing centering prayer techniques said, "In diverting our mind from all images, meditation can afford us a sense of tranquility, of peace, release from time and space, but there is no feeling of standing before a personal God. It is not real prayer-face to Face.(On Prayer pg.139)." According to Elder Sophrony's teachings repetitive forms used in the Jesus prayer must oriented toward knowing and loving a personal God. We do not use them to enter states of mind or to somehow manipulate God. As the Elder said real prayer is "face to Face".
When oriented properly the repetition used in the Jesus Prayer helps a person grow in their personal relationship with God. However, it's important to understand why we use repetition in the first place. It's easy to understand why we do it but often we lack the knowledge associated with the tradition. First of all, we were created with the propose of loving God for all eternity. Every aspect of what we are was geared toward developing a personal relationship with God, which would include our mind and body. Next, because of sin there was a disorientation in how we were naturally geared toward God. Being obscured the body and the mind were no longer used for their original purpose. Third, in the work of Jesus Christ and his Church we find a way back to what we were originally created for. In the spirituality of the Church we discover various systems that help return the body and mind to their original purpose. In conclusion, There are many forms of discipline in the Church that we use to struggle against are sinful condition. The use a repetition in the Jesus Prayer is way to recondition the body and mind to their original use.
Repetition used in praying the Jesus Prayer has taken on many forms in the history of the Byzantine tradition. Many of us know the popular usage that involves inhaling(Lord Jesus Christ, Son of God) and exhaling(Have mercy on me a sinner) a method that's often used in conjunction with a prayer rope. St. Nicodemos in his instructed went a little further with this method in his day. He instructed his followers to hold their breath and say the whole prayer in the mind and then exhale. A method that demonstrates well how the mind and the body are reconditioned back toward God. In this way the mind is disciplined to overcome its tendency to wander in prayer with the body's help. In all the forms that we can find in the history of the Byzantine tradition the goals are always the same, which are to return the body and the mind to the proper use.
There really is nothing vain about our use of repetition in our Byzantine tradition if we understand it. The use always involves personal salvation. One of our spiritual fathers demonstrated this in his instruction on repetition of the Jesus Prayer. He said that the prayer must be prayed with the same intensity as one drowning at sea who calls for help(over and over again) with all their might hoping that someone will hear them. Likewise we call out to God focusing all our energy upon the single prayer hoping to seek our own salvation. Unlike someone who is drowning in a sea we know our God is listening. His arms are always reaching down to us ready to pull us into His embrace. It could be said that the repetition that we use in Jesus Prayer is our way to open our arms to God.
To read about controlled breathing in the Jesus Prayer (click)