The teachings of Guru Nanak Dev Ji, the first guru and founder of Sikhism, focus on the pursuit of spiritual knowledge, ethical conduct, and justice. His teachings emphasize the following basic principles:

1. Oneness of God (Ek Omkar):
Guru Nanak Dev Ji emphasized belief in the formless, eternal God who is the creator of the universe and exists in all living beings. This is embodied in the popular phrase "Ek Omkar," which means "there is only one God." God is beyond human understanding, but accessible through love and devotion.

2. Equality of all human beings:
Guru Nanak's teachings emphasize the equality of all people, regardless of caste, sex, race, or religion. He opposed discrimination and social injustice. He said, "No one is superior or inferior, all are equal in the eyes of God."

3. Selfless service (Seva):
Seva or selfless service is central to the teachings of Guru Nanak Dev Ji. He believed that serving the world without expectation of reward is a way to connect with God and purify the soul.

He also established the practice of langar. The service spirit of a servant providing free food to people emphasizes the importance of humility and sharing.

4. Truth (Sat):
Guru Nanak Dev Ji emphasized on living a true life, being honest in thoughts, words and deeds. He taught that truth is the foundation of spiritual growth and one should always strive to live according to the truth.

5. Meditation on the name of God (Naam Simran):
Guru Nanak Dev Ji taught that remembering and meditating on the name of God (Waheguru) leads to inner peace, spiritual enlightenment and liberation. This practice is central to Sikh worship and daily life.

6. Rejection of superstitions and customs:
Guru Nanak Dev Ji rejected the customs, superstitions and empty rituals prevalent in the society of his time. He believed that spiritual development depends not on external rituals but on internal devotion and religious activities.

7. Live an honest life (Kirat Karna):
Guru Nanak Dev Ji advocated earning a livelihood through hard work and honesty without exploiting others. The principle of livelihood "Shram" teaches that one should live honestly and avoid dishonest means of earning.

8. Sharing with others (Band Chhakna):
Guru Nanak Dev Ji promoted the idea of ​​sharing one's wealth and resources with the needy. This practice encourages generosity and community spirit. Sharing is not just about material wealth but also about sharing knowledge, kindness and compassion.

9. Universal community of humanity:
Guru Nanak Dev Ji saw all human beings as part of one family. He rejected the division of people based on religious, ethnic or social differences. His teachings advocated peace, understanding and community.

10. Spiritual salvation (Mukti):
According to Guru Nanak, the ultimate goal of life is to achieve spiritual liberation, which can be achieved through devotion to God, virtuous living, and service to others. Liberation means freedom from the cycle of birth and death (samsara) and union with the divine.

Guru Nanak's teachings guide Sikhs and people of all religions to lead a life of piety, compassion, and devotion.