Ninshū (忍宗; Viz "Ninja Creed"; Literally meaning "Shinobi Sect") is the religion and the peaceful precursor of modern ninjutsu created by Hagoromo Ōtsutsuki, the first one to understand and teach the mystery of chakra. The teachings of ninshū were meant to give people a better understanding of themselves, as well as others, and lead the world into an era of peace. Unfortunately, Ninshū would eventually come to be known as ninjutsu, a more weaponised version of the Sage's teachings.
Hagoromo exemplified his teachings by distributing chakra meant to "connect" people's spiritual energies with one another. It would allow people to understand each other without communication and would allow them pray for each other's safety. However, people didn't use the chakra to connect with others, but to instead connect their inner spiritual and physical energies together. They kneaded their inner chakra to amplify it and transform it into modern-day ninjutsu. In the end, they ended up using their chakra in battle, just as Hagoromo's mother Kaguya did.