We find an interesting parable in Lotus Sutra,one of the several Buddhist texts.It is about a Physician & his sons.The story goes like this:
A well trained physician who has been away from home for a long time returns to find that his sons had taken poison & are seriously ill.He sets about preparing an excellent remedy according to his knowledge of medicine.After the remedy is prepared,some of his sons take the medicine & are cured of illness.Other sons,however,think that they have already been deeply affected by the poison.So,they refuse to take the medicine & continue to grieve in their illness.
Seeing this,father devises a way in order to induce rest of his sons to take the medicine.He tells them he has already advanced in years & his death is near,he has to visit other country.He goes away & sends a message to the sons about his death.The sons are shocked.Thinking that their father would never return again,they take his medicine & get cured.
Through this parable,we are given to understand that Buddha appearance in the world was like the return of physician from distant nation.When Buddha saw that people of the world have consumed the poison of greed,anger,delusion & are distressed & suffering;he devises a cure for their suffering,which is the Dharma-path to liberation.
Some of the people (his disciples) immediately take this remedy & are cured.While there are others,who are deeply affected by poison of greed,ignorance & anger;refuse to take the medicine.As a result,a device has to be employed to encourage them to take the medicine,follow the path & achieve liberation.That device is the apparent extinction of the Buddha.
Although the World perceived the birth of Siddhartha Gautama,the event of his great renunciation,the years of his struggle for Enlightenment,his attainment of Enlightenment under the bodhi tree,his 45 years of teaching & his passing away at the age of 80;all this was in fact merely a show for the purpose of enlightening sentient beings.(As appalling as it may seem!)
The terrestrial dimension of Buddhahood can assume any form & any number of forms.It can not only assume a recognizable & special form like Siddhartha Gautama but also the form of a friend or an enemy or like,in order to benefit & liberate sentient beings.
In addition to animate beings,Bodhisattvas can also assume the form of inanimate things such as food,cloth,books,etc.
Every human being on our planet can begin his spiritual journey towards Enlightenment,no matter where he stands at the present moment of life.Once you begin your journey,each person & situation helps you to progress on that path,but the path must be traveled by you & only you.