The core of Guru Nanak's teachings is the idea of "Ik Onkar," which emphasises God's unity. The words "There is but one God, His name is Truth, He is the Creator, He fears none, He is without hate, He never dies, He is beyond the cycle of births and death, He is self-illuminated, He is realised by the kindness of the True Guru" are spoken by Guru Nanak in the Guru Granth Sahib Ji (Guru Granth Sahib Ji, Japji Sahib). This declaration, which cuts over socioeconomic, religious, and cultural divides, establishes the groundwork for the unification of humanity

Also Read: Guru Nanak's legacy: Teachings of unity, equality, and compassion in the Guru Granth Sahib Ji

Paramjit Singh Sachdeva, a Ph.D scholar writes that along with the new teachings, he also imparted wisdom on how we should connect to one another and the Creator God. “He placed great emphasis on the unity of God and humanity.  A God of Justice and Forgiveness, Love, Mercy, and Compassion,” Sachdeva writes in “The Life and Legacy of Guru Nanak Sahib Ji”

Guru Nanak vehemently advocated for the eradication of social hierarchies and discrimination. His teachings explicitly reject the caste system and emphasise the inherent equality of all individuals. The Guru Granth Sahib Ji declares, "One who recognises the One Lord among all beings does not talk of ego. O Nanak, he knows the way" (Guru Granth Sahib Ji, Siri Raag). This commitment to equality and justice serves as a timeless inspiration for Sikh communities striving to create a society free from prejudice

“Unlike other medieval poet saints, the Guru also spoke emphatically of collective liberation and went beyond singing about human equality to actually challenging the Hindu caste hierarchy by starting the langar (communal meal), which represented rejection of any social, age, or gender-related distinctions,” says Gurinder Singh Mann of the Global Institute for Sikh Studies

The lessons of Guru Nanak place a strong emphasis on compassion for all living things and selfless service, or seva. Beliefs are encouraged to perform deeds of love and service to mankind by the Guru Granth Sahib Ji. "The skies celebrate the unselfish work of the Lord's followers. They are the most beautiful of the beautiful; words cannot express how magnificent they appear, O Siblings of Destiny (Guru Granth Sahib Ji, Maru Sohale),” These verses encourage Sikhs to actively engage in altruistic activities and make contributions to the betterment of society

Guru Nanak promoted a spirit of religious tolerance and acceptance