Perfection is the final state when all things come into there own and there are no flaws, no weaknesses, no faults at all, and perfect peace.
It is what we seek to spiritually achieve, which in actuality, is an infinite process. We cannot achieve perfection, as there is no limit to knowledge, wisdom, understanding or truth. As the mind and spirit grows, their capacity is increased. If we could achieve perfection however, evolution would be meaningless.
As we evolve, more of the unexpressed self surfaces, which means more of perfection is being expressed, and as such the closer we are to the Collective Spirit.
Whilst the Law is perfect, we are imperfect, and the perfect Law cannot operate through us. This Law is perfect in its operation. It is akin to perfect light reflecting through badly polished mirrors. That which we regard as evil is only imperfection, imperfectly expressing the Collective Spirit through it.