Some religions think you need equal out the good and evil in your own personal life to help balance the universe. It's new agey, illuminati, devil-woshipping bullshit.
ahz
I would say that it predicates that evil cannot exist without good. They tend to be in balance in the world as a whole, but do not need to be balanced in an individual or even a society
Manichaeism or dualistic religions are hardly 'new age' as they preceded christianity
Moral dualism
Moral dualism is the belief of the coexistence (in eastern and naturalistic religions) or conflict (in western religions) between the "benevolent" and the "malignant". Most religious systems have some form of moral dualism - in western religions, for instance, a conflict between good and evil.
Like ditheism/bitheism (see below), moral dualism does not imply the absence of monist or monotheistic principles. Moral dualism simply implies that there are two moral opposites at work, independent of any interpretation of what might be "moral" and - unlike ditheism/bitheism - independent of how these may be represented.
Ditheism/Bitheism
In theology, 'dualism' may also refer to 'bitheism', 'duotheism' or 'ditheism'. Although ditheism/bitheism imply moral dualism, they are not equivalent: ditheism/bitheism implies (at least) two gods, while moral dualism does not imply any -theism (theos = god) whatsoever.
Both 'bitheism' and 'ditheism' imply a belief in two equally powerful gods with complementary properties. However, while bitheism implies harmony, ditheism implies rivality and opposition, such as between Good and Evil. For example, a ditheistic system would be one in which one god is creative, the other is destructive (cf. theodicy). In a bitheistic system, one god could be male and the other female (cf. duotheism). However, bitheistic and ditheistic principles are not always so easily contrastable, for instance in a system where one god is the representative of summer and drought and the other of winter and rain/fertility. (cf. the mythology of Persephone)
The 'di-'/'bi-' ('two') prefix in 'ditheism' and 'bitheism' does not imply that such a religious system cannot also be monist. Zurvanism (Zurvanite Zoroastrianism), Manichaeism and Mandaeanism, all three of which are representative of dualistic philosophies, are also monist religions since each has a supreme and transcendental First Principle from which the two equal-but-opposite entities then emanate. This is also true for the lesser-known Christian gnostic religions, such as Bogomils, Catharism, etc. These may then be contrasted with Marcionism, which held that the Old and New Testaments were the work of two opposing gods with neither having a superior instance (both were First Principles, but of different religions). More complex forms of monist dualism also exist, for instance in Hermeticism, where Nous "thought" - that is described to have created man - brings forth both good and evil, depending on whether it receives input from God or from the demons.