This Q's answer given by Pujya S.N.Goenka To verbal & non verbal Mantra practitioner's from all sect.
Q.
In India recitations, mantras and visualization are very important in meditation. Why do you insist that we should not give attention to these and instead devote our attention to pure respiration and sensations?
Pujya Guruji :
We are not against verbalization or visualization; they have their own value and are wonderful aids to concentration. If you keep imagining a shape, especially the shape of someone in whom you have great faith, your mind will calm down and become concentrated. Similarly if you mentally repeat a particular word, the mind will calm down and it is also purified. However, it is only purified on the surface; the impurities remain suppressed deep inside.The aim of Vipassana is not merely to concentrate the mind nor to purify it at the surface level, but to purify it at the deepest level.Every word has its own vibration, and especially those words called bīja mantras [seed mantras]. If you keep repeating them you get engulfed in a created, artificial vibration, and this is good to some extent because it acts like a shield and doesn’t allow some bad vibrations to disturb you. But your deep-rooted impurities don’t have a chance to be eradicated; and also, you won’t discover what happens to your body and mind when you generate impurities like anger, fear, passion or ego.Any kind of impurity generated in the mind is bound to create a sensation on the body because mind and matter are so interrelated that they influence each other. If the mind has a positive thought you find pleasant sensations. If the mind is full of negativity you find unpleasant sensations. This is the law of nature. When an impurity in the mind generates an unpleasant sensation you react to that sensation with aversion, and this reaction itself creates a particular type of unpleasant sensation, and in turn you react to this. So your reaction to the impurities multiplies because of these sensations, and the sensations multiply because of the impurities— a vicious circle starts.The Buddha discovered that to break this vicious circle you must observe sensations objectively, understanding that they are anicca. This is because vedanā-paccayā taṇhā—dependent on sensation, craving arises. It is only pleasant sensations on the body that make you generate craving and clinging, nothing else. It appears as though you are craving something outside—an external form, sound, smell, touch, or taste—but there is a gap between the outside object and your reaction to it.That gap was discovered by the Buddha and was his Enlightenment.It is not saḷāyatana-paccayā taṇhā—dependent on the sense objects, craving arises. But instead saḷāyatana-paccayā phasso; phassa-paccayā vedanā; vedanā-paccayā taṇhā—dependent on the sense objects, contact arises; dependent on contact, sensation arises; dependent on sensations, craving arises. This missing link was discovered by the Buddha. If you don’t make use of it, you are not following the teaching that will take you to the final goal.When people are involved only in created vibrations or imaginary forms they give no importance to natural sensations; but if they start working with natural sensations they go to the deepest level of their minds and eradicate their impurities.We are not here to condemn others who use verbalization or visualization, but those who have confidence that this path will take us to the final goal certainly have to understand the importance of vedanā. Whether the vedanā are pleasant, unpleasant or neutral, observe them with anicca. As your understanding of anicca becomes stronger, this purifies the depths of the mind and you reach the final goal that is beyond vedanā.
Be Happy, Be Liberated !!!