In an address from 1971, Dr. George King explained why mental self-control is important during prayer:

“The prayers you said this morning have gone up from this church, and they are coloured by your own thought—if, during the time you are saying a prayer, you thought of something else, you introduced different colours, different frequencies of energy into that initial prayer. It’s that obvious—I mean this is basic metaphysics. This is something we learn I think, or should learn, in our first grade in metaphysics. 

“Very well then. You can see the importance of mental control. And mental control can only be brought about by practice.”

Performing The Twelve Blessings, or any correctly-balanced prayers, is a wonderful way to practice mental self-control and thereby improve our concentration. Each time we say these prayers with our full effort and attention, our mental self-control gets better.