A human being has two bodies – the gross body (sthūladēha) and the subtle-body. Along with this he has Vital energy (Prāṇa-shakti) that links these two bodies together. Understanding this point will help us to see why people need spiritual help after death. See the diagram given below.
Note: In order to understand this article better, it is recommended that you read the article Where do we go after death?
When one dies, the vital energy is released back into the universe. The physical body remains on the Earth region (Bhūlok) while the subtle-body travels to a subtle-plane depending on its merits or sins and its spiritual level. The subtle-body becomes heavy due to sins and excessive ego and as a result gets stuck in lower subtle-planes of existence such as the Nether region (Bhuvarlok). If the sins are intense then the subtle-body goes to Hell (Pātāl).
On the other hand, the subtle-body becomes lighter due to good deeds (merits) and the intensity of spiritual practice. The higher the spiritual level, the lighter the subtle-body and faster the progress during its sojourn.
After death, those whose spiritual practice is not intense, get stuck in the Nether region. A seeker’s subtle-body crosses the Nether region immediately due to the lightness of the subtle-body as a result of spiritual practice and goes to higher subtle regions of existence such as Heaven (Swarga).
However, the subtle-body without the strength of spiritual practice remains in the subtle Nether region and has to undergo the distress there. It doesn’t gain momentum because it lacks spiritual energy and purity (Sattva predominance) and hence is stuck in the heavy atmosphere of the subtle Nether region.
They need spiritual help to make their onward journey. Now, they can turn only to their descendants to do something for them. As the descendants are benefactors of the assets of their ancestors in one way or another, they are spiritually bound to render requisite help to these subtle-bodies. However, the descendents in many cases are unaware of the rites and rituals that need to be done in a correct manner according to the science of Spirituality to assist their deceased ancestors. As a result, the ancestors who have passed away get no relief in the subtle Nether region. The ancestors therefore trouble (as mentioned in an earlier article) their descendants, in order to draw their attention towards them. When the descendant in the Earth region experience difficulties that just don’t seem to go away, they start looking for solutions beyond conventional means. In some cases, the troubled family members turn to spiritual help that brings some relief to the departed ancestors.