Whenever there is mention of human welfare, Lord Buddha will be taken as its synonym. It is well known that once when he went around the city on royal chariot, he came across an old man, a sick man, a dead body, and an  ascetic. The scene agitated his heart. All previous beliefs, instructions, and visions vanished. And then was born a new Siddhartha. The world, death, birth, afflictions, old age, separation from the loved one, and unpleasant all are sorrows. On one hand, the mankind has been trying to get rid of these sorrows, on the other it has taken them as destiny. Buddha said, “Man himself is responsible for his sorrows”. There is nothing in the world which is without cause.Every mental state is born of other mental states and is still so caused by others. And thus the process of creation, i.e., Bhav Chakra (wheel of becoming) is ever active. Things are interdependent, relative and sanskarita. This is known in Buddhist literature as the law of “pratitya samutpada” i.e., if there is sorrow there is also its cause, elimination and control through the following of the ” Eightfold noble path” (ashtangika arya marga). It means right view, right resolution, right speech, right action, right livelihood, right effort, right mindfulness and right concentration.
The correct vision resulting from realization of reality destroys the false vision. Following this eightfold path the suffering mankind may achieve a peaceful and tension free life. This is the path of self purification which is summarized by Buddha as :
” Sabba papassa akarnam, kusalassa upa sampada
Sacitta pariyodapanam, etam Buddhanusasanam”.
(“Abstinence from all evils, fulfillment of all good, purification of one’s mind.” is actually Buddha’s preaching.”)
The  end of sorrow is Nirvana which is indescribable. The elimination of the cause of sorrow is the end of suffering. Nirvana is nothing but absence of desire (trisna). It is calm mental state, liberation, end of sorrows, supreme bliss, supreme peace and termination of the worldly cycle (bhava-chakra).
In  renouncing worldly life, the lord was leading a life of apassion, (vitaragi) in the forest of Urubela. He lived the austere life of an ascetic.  Performing many experiments on himself, he finally reached the conclusion that we should keep away from extremes. He said, “Neither keep lute (vina) strings so loose that musical notes do not come, nor tighten them so much that they snap.” He was a scientist. Buddhist philosophy is based on reason and science the great scientist Einstein said, “If there is any scientist religion in the world it is Buddhism and its middle path liberty goal to adjust the rules of time and place; to establish room for logic and its verification; to eliminate devoid of superstitions and ostentations. It is standing upright on solid foundation of science.”  This is why many thinkers and philosophers like Dr. Ambedkar, Rahul Sankrityayana, Anand Koushalyaya consider it relevant for human welfare; modern India has embraced it.
Buddha is the only visionary whose religion is humancentric. His first principle is man’s duty to others.It has nothing to do with soul and soul. The world is full of sorrow and the aim of religion is to eliminate it. Other than this, there is s nothing. Buddhism declares man as master and controller; on the other hand, it tries to make man superior by extolling good conduct.Remember in Buddhism, good conduct has the same place as God or Allah in other religions. Man’s welfare require observance of “panchasila”; this is manadatory.
1.  Refrain from killing leaving beings.
2.  Refrain from stealing.
3.   Refrain from sexual misconduct.
4.   Refrain from telling a lie.
5.   Refrain from taking intoxicant.
These things distinguish Buddha and his religion from others. Buddhism neither makes man god nor demon, high or low. It makes all equal !!
Equal are all, neither slave nor master.
In this respect, Buddhism is an invention, a discovery that human life is a state of serious study and complete understanding of human instincts along with those tendencies giving birth to human history which may become the cause of his destruction. Buddha merely shows the path, he does not bestow liberation. Each has to work for his own liberation..Buddha never claimed that he was infallible. Every one has right to ask, test, and observe if one is on the noble path or not. He never declared any one as his successor. Religion alone is his successor.
He challenged the prevailing system. Man is just man. There can’t be any caste. Merit on basis of birth is outright wrong. Following culture of action instead of culture of birth is the only way for human welfare. He denied yajna, havana, sacrifice, puja and physical mortification.
He preached, “Be thy own lamp.” Eliminate your sorrow with your own efforts that you have verified on your own. What is required is to make all improper things proper in life. Every one is born with potentiality of enlightenment. One should try to work for enlightenment. Buddha is unique in all the world civilizations,because he gives so much importance to man. The basis of religion is that which is natural in life and events governed by natural laws.
When we think honestly, we realize that human welfare is only possible when our life is governed by correct prajna (wisdom), Samadhi and shila. The sorrows of the ignorant have a beginning but no end. So long as humanity consider others as the cause of its sorrow and worships and waits for some liberator its sorrow will increase. Buddha in renouncing his royal privilege presented a path for mankind to ponder; since then , man has been to secure its welfare. How can there be any path superior to it.
One may question whether there has been exploitation of man in other religions and by other leaders. Buddha with great courage exposed evils in name of religion and said that unrighteous religion has to be renounced. Unrighteousness has been centered on the innocent and illiterate in religions for ages. Buddha was the great warrior who raised his voice against it. He also spoke about the limits of religion. Religion is not an end in itself but a means to reach the end. Man is not for religion but religion is for man. Buddha compared religion to using a raft to cross a river and then leaving it; it is not to be used and abandoned. It is a secret means to reach a sacred end.
The whole world bows its head before Sakya, Muni, Gautam Buddha who showed the path of friendship, love, and sympathy for human welfare.
Homage to him the exalted one, the blessed one, the fully enlightened  one