Sikhism developed from the spiritual teachings of Guru Nanak (1469–1539), the faith's first guru and the nine Sikh gurus who succeeded him. The tenth guru, Gobind Singh (1666–1708), named the Sikh scripture Guru Granth Sahib as his successor, bringing to a close the line of human gurus and establishing the scripture as the 11th and last eternally living guru, a religious spiritual/life guide for Sikhs. Guru Nanak taught that living an "active, creative, and practical life" of "truthfulness, fidelity, self-control and purity" is above metaphysical truth, and that the ideal man "establishes union with God, knows His Will, and carries out that Will Guru Hargobind, the sixth Sikh Guru (1606–1644), established the concept of mutual co-existence of the miri ('political'/'temporal') and piri ('spiritual') realms.
The Sikh scripture opens with the Mul Mantar (ਮੂਲ ਮੰਤਰ), fundamental prayer about ik onkar (ੴ, 'One God'). The core beliefs of Sikhism, articulated in the Guru Granth Sahib, include faith and meditation in the name of the one creator; divine unity and equality of all humankind; engaging in seva ('selfless service'); striving for justice for the benefit and prosperity of all; and honest conduct and livelihood while living a householder's life.Following this standard, Sikhism rejects claims that any particular religious tradition has a monopoly on Absolute Truth. Sikhism emphasizes simran (ਸਿਮਰਨ, meditation and remembrance of the teachings of Gurus). which can be expressed musically through kirtan, or internally through naam japna ('meditation on His name') as a means to feel God's presence. It teaches followers to transform the "Five Thieves" (i.e. lust, rage, greed, attachment, and ego).