The Yogasutra of Patanjali is one of the ancient sources to understand what it means to follow the path of realisation. It leads to the realisation of our godlike nature. Still it’s not the complete freedom as it is descent in the teachings of Buddha Siddharta Gautama. His noble-8-fold-path leads to the freedom from saṃsāra: the suffering from dying and rebirth.
A good english Translation of the Yogasutra-of-Patanjali from Cip Hartranft can be found under this -> Link.