In Nikāya Buddhism, the bodhisattva image is restricted to Śākyamuni Buddha himself. In this system, a bodhisattva is not a general term describing an open concept. It is an image of an ideal follower of Buddhism, namely Śākyamuni. However, in Mahāyāna Buddhism, anyone who makes a vow to practice Buddhism for the benefit of others can become a bodhisattva and put such practices into action, hoping to become a buddha at some point. So for anyone practicing as a Mahāyāna Buddhism, the concept of the bodhisattva spread as an open image that all followers should try to achieve.