Guru Nanak is known as one of the most popular saints in India and also the youngest founder of Sikhism. Guru Nanak has established the religion of Sikhism in India and spread his idealism through all over the world with the help of his disciples. He has followed almost all the methods like gentle persuasion, humour, sarcasm and even admonition to get his point across and spread the Sikh faith. He took a strong stand against some of the social customs in India, in the fifteenth century. The medieval Indian society was divided into two distinct and mutually antagonistic religious groups - pan-Hinduism and Islam at that time and there were distinct strands and various shades of persuasion, within each group. Guru Nanak appeared in such a period. Guru Nanak`s teaching reflected his deep philosophical understanding. He spread the message, "There is no Hindu, no Mussalman" and also said that all are creatures of God and His creation.

Guru Nanak strongly believed in the view that there is only One God and there are numerous ways to reach Him. He clearly declared this stand at a time, when the fight was between "my way to my God" and "your way to your God". The prominent religions in India at that time included the likes of Hinduism, Buddhism, Jainism, Vashnavites, Shaivites, and Nath Yogis. There were also a number of castes in the Hindu faith like the Brahmin, Kshatriya, Vaish and Shudra. On the other hand, there were two traditional divisions like Shias and Sunnis in the Islamic society also. Guru Nanak strongly stood against these kinds of segmentations and said that there is no difference between any of the creatures of the God and everyone is equal. He said, "The caste of a person is what he does". He maintained this throughout his entire life and also set out to dissolve differences through the institutions like sangat and pangat.

In the teachings of Guru Nanak the life of the Siddhs or holy men, who had renounced the world and lived their lives in the hills were criticised. Nanak said that the life of a religious person was a life lived piously, in toto and he disliked the luxury of an escape from the responsibilities of a householder. According to the teachings of Guru Nanak, it is through good conduct and the recitation of the Name of the Lord that a person would attain mukti, or the freedom from the endless cycle of life and death. He never suggested the life of a mendicant to his followers and Nanak`s disciples had to participate in worldly affairs and take care of their family responsibilities. Above all, they had to live as good human beings.

The teachings of Guru Nanak clearly stated his view about religion and religious person also. Guru Nanak said, "Religion consists not of mere words. He who looks upon all men as equal is religious". He always strongly promoted universal brotherhood in his bani, and for him, God was the binding force, not a divisive "my" or "our" God. Nanak said that nobody can find this God in remote temples or far away places and as He is immanent, He is found everywhere.

Guru Nanak strongly supported religious practice among women and said that women can also attain mukti, as the way to realisation of God is open to all human beings. Nanak said this at such a time, when women were treated as inferior to men and impure and it was also said that one had to be born a man in order to attain mukti. Nanak criticised labelling women as "impure" and said in the holy book of Sikhs, Guru Granth Sahib, "Why revile her, of whom are born great ones of the earth".

The teachings of Guru Nanak stressed on forgiveness as an essential element of human interaction. He said that there are millions, who have perished for want of compassion and forbearance. He often came across intolerant people, during his travels; however, he always forgave them and said that it is stupid to entangle oneself with a foolish person. Nanak was always concerned about the ordinary people and his compositions mainly reflect the language of the people of his period.

The teachings of Guru Nanak include the following:

He discarded worship of images.

He regarded himself as the prophet of God.

The Hindu and Muslim saints are the diwans in attendance upon the preserver.

He used both Hindu and Muslim nomenclature for God such as Rama, Govinda, Hari, Murarl, Rab and Rahim.

He tried to unite the Hindus and the Muslims in an unbreakable bond of love and mutual understanding. He considered Hinduism and Islam as two ways but the God of both is one.

He emphasized unaffected faith in Guru and loving devotion to God.

He condemned superstitions and formalism of both Hinduism and Islam.

He rejected practice of austerities, fast, wearing sacred thread or ragged clothes and considered going about bathing at the places of pilgrimage as useless.

He laid emphasis on moral virtues such as mercy, contentment, continence, truth, benevolence, faith, honesty, humanity and civility. According to Nanak Truth is higher than everything but higher still is truthful conduct.

He regarded all men as children of the same God and taught sympathy and compassion for the whole of human race.

He was against caste system. According to him a man should be honoured for his devotion to God and not for his social position. He did not like the haughty attitude of the highborn priestly class and started common kitchen for all his followers to remove caste distinctions.

He condemned those who regarded women as impure.

According to Nanak man is the maker of his own fortune. There is nothing like predestination.

He considered education essential for the attainment of true and complete life.

The teachings of Guru Nanak have a universal appeal and provide answers to the myriad social and ethical problems that the people face even today, and will most probably face tomorrow. According to him, education alone is not enough and "The educated should be reckoned ignorant if he shows greed and ego". Guru Nanak`s compositions contain truths that pertain not only to the religious aspect of people`s lives, but also the social and family matters, something that have been ordinarily considered outside the horizon of religion. Guru Nanak actually presented the world a simple, non-ritualistic religion that allows its followers to live a religious life, while taking care of their worldly duties, all at the same time.