“Vipassana meditation is something of a mental balancing act. You are going to be cultivating two separate qualities of the mind--mindfulness and concentration. Ideally these two work together as a team. They pull in tandem, so to speak. Therefore it is important to cultivate them side-by-side and in a balanced manner. If one of the factors is strengthened at the expense of the other, the balance of the mind is lost and meditation impossible.
Concentration and mindfulness are distinctly different functions. They each have their role to play in meditation, and the relationship between them is definite and delicate. Concentration is often called one-pointedness of mind. It consists of forcing the mind to remain on one static point. Please note the word FORCE.
Concentration is pretty much a forced type of activity. It can be developed by force, by sheer unremitting willpower. And once developed, it retains some of that forced flavor. Mindfulness, on the other hand, is a delicate function leading to refined sensibilities. These two are partners in the job of meditation. Mindfulness is the sensitive one. He notices things. Concentration provides the power. He keeps the attention pinned down to one item. Ideally, mindfulness is in this relationship. Mindfulness picks the objects of attention, and notices when the attention has gone astray. Concentration does the actual work of holding the attention steady on that chosen object. If either of these partners is weak, your meditation goes astray….”