YOGA or union is the culmination of spiritual practice and not merely the practice itself
The perfection of the imperfect is to be achieved before union is possible. The core of the training is cleaning of the samskaras enveloping the soul, meditating on the light in the heart and daily prayer. With regular practice, the mind becomes pure and healthy. This is when you need a spiritual master.
In spritual training, transmission is important. A spiritual master has the capacity to transmit yogic or life energy from his own centre of existance to the centre of existance of another individual, the spiritual seeker or disciple.
When the transmission takes place, the practitioner is filled with a force higher than himself and his evolution of progress becomes not only speedier but also independent of his own capacity for progress. You can experience growth without limitations. With the guru's power, all past impressions or samskaras that crowd the mind are erased. The mind is not controlled, it is regulated. The mind is made to focus on a single subject ; intruding thoughts drop-off.
In economic terms, the practitioner's first fruit is increased productivity, zero-defect work and quick learning. They become better administrators, managers, businessmen and employees with-out losing sight of the human, ethical aspects. Such practitioners are transformed into better human beings. Meditation helps the seeker experience the highest degree of transformation.
To experience all this there is only one way ! Practice and experience that higher state. It is said that, to experience swimming you should simply start swimming. You have to be willing to try.