Please read the following important quotes from Ch'an Master
Sheng Yen. They tell you why it is necessary to take refuge
in the Three Jewels.
http://www.dharmadrum.org/content/chan_garden/chan_garden2.aspx?sn=40
Why is it important to Take Refuge in the Three
Jewels?
... Participating in the ceremony of taking refuge in the Three
Jewels is the first, important step for anyone who wants to become
a Buddhist. Why? Because the heart of Buddhism is the Three Jewels
of the Buddha, Dharma, and Sangha...
... [Taking refuge] is about committing one's life towards a
path to awakening, which is, in fact, freeing not binding ... If we
realize that the Buddhist teaching is beneficial or meaningful in
our lives, then the next step is to take refuge in the Three
Jewels. When we become Buddhists, we commit ourselves to bringing
genuine liberation to ourselves and to everyone around us. This is
the Buddhist path ... Trying to learn Buddhism without
taking refuge is to be a bystander and not a
participant...
... Those who believe that having a pure, sincere heart is
enough to qualify them as Buddhist practitioners and who see no
need to go through the formal refuge ceremony, are not really
Buddhists. If you want to get an education, you must first register
and then proceed through elementary, middle, and high school until
you reach college—perhaps reaching as far as a Ph.D. It is
impossible to progress in one's education without taking these
successive steps.
Similarly, self-proclaimed Buddhists are not real
Buddhists. They are like people who are fond of
another country, emigrate there, pretend to be citizens, but never
apply for citizenship. Those who refrain from taking refuge, but
insist upon calling themselves Buddhists, may glean some benefit
from the teachings, but the essence of Buddhism will always elude
him. Taking refuge is a required process, not an option.
The sutras or Buddhist scriptures tell us that even people who
perform good deeds will not be able to eradicate bad karma unless
they take refuge in the Three Jewels...
... Some people believe that their comprehension of the Buddhist
sutras, which they take to be one and the same as the Dharma, is
sufficient to enable them to advance directly to full
enlightenment. They see no need to practice meditation or receive
the Three Refuges. While this may have its appeal, it is a serious
mistake.
The Buddhist sutras were taught by the Buddha and his disciples,
and later collected and written down by members of the Sangha.
Concentrating on these texts only yields a limited understanding of
the Dharma Jewel. This would lead us to disregard the Buddha, who
gave these teachings, and the Sangha, who spread the Dharma.
Buddhism stresses the Dharma—the path which leads to the ending of
suffering—only in conjunction with the Buddha and the Sangha.
The three are inseparable. It is true that taking refuge
requires investigation of the Buddha's teachings, but it also
necessitates participation in the refuge ceremony, which must be
conducted by a precept master, who is usually a member of the
Sangha. This confers the formal recognition that you are a
Buddhist...
... Lastly, I must stress that taking refuge in the Three Jewels
is only the first step in becoming a Buddhist.
Once we have taken
refuge, we must embark on the path of spiritual cultivation, which
involves finding a teacher and developing a regular
practice. Doing so will decisively set you on the Buddhist
path of awakening to wisdom and compassion...