Karmic obstacle is the negative ‘effect’ derived from the law of cause and effect. In other words, it is the effect that you have derived from the cause that you have sowed.
When an evil deed, speech or even thoughts are committed, a lump of dark energy is formed from an energy field onto the consciousness of your soul; this lump of dark energy will enter into your body. Subject to the severity of karmic obstacles, it will come into existence in various parts of your body. With that, some people may experience immediate retribution, while in others it will develop into karmic obstacles on certain part in the physical body. That is why karmic obstacle is referred to as the dark energy of the soul.
Karmic obstacles are like the viruses in a computer program hiding in a person’s Alaya Consciousness. When the right time comes, they will be incited into foreign spirits and take effect on the person. This explains why a perfectly healthy person suddenly becomes critically ill, gets involved in an accident or meets with a catastrophe. There are some whose karmic obstacles are so weighty that they constantly face problems throughout their lives, and their complexions are dull. They always blame everyone and everything but themselves.
If one continues to commit evil deeds and acts of killing in this life, even if they have residual karmic rewards, their evil deeds will also transform into karmic obstacles which will be deposited in the Alaya Consciousness. Alaya Consciousness is the Eighth Consciousness – the fundamental consciousness. In this level of consciousness, there are countless seeds, that could trigger a person’s kind or evil behaviour (it predominantly refers to a person’s line of thought). For karmic obstacles stored in the Alaya Consciousness hereto, ONLY significant meritorious blessings are able to penetrate and counteract, resulting in the effect of its purification.
When Master Lu reads the totem of a person, karmic obstacles will appear as dark energy in blocks. If the blocks of dark energy are substantial, it depicts that the person has committed many wrongdoings in his past and present life; in that case, their health, career and relationship will be unfavourable.
Karmic obstacles can only be transformed in two ways: either it is counteracted upon or it will transform into foreign spirits and be activated. Having good karma is one method to eliminate karmic obstacles. In fact, there are no other powers that can affect them besides this. The good karma here refers to meritorious blessings as it holds the power to counteract karmic obstacles. Hence, “the body is a Bodhi tree, the mind a standing mirror bright. At all times polish it diligently, and let no dust alight.” We are reliant on our meritorious blessings to purify the “dust” in our mind.
Buddhism in Plain Terms Volume 1 – Chapter 8 & 11< Buddhism: Your Questions Answered