The Buddha elevated a number of disciples to the appointment of Great Disciple. For example, Sāriputta was the Marshal of the Dhamma. Mahāmoggallāna was the Master of Psychic Powers. Mahākassapa was the Foremost among the Bhikkhus who Observed the Austere Practices. Ānanda was the Guardian of the Dhamma.
But this title was not bestowed at the Buddha’s whim. According to the Theravādan tradition, the path to great discipleship is a long one. It is a path that begins with a deep aspiration. It is spread across lifetimes and across realms and planes of existence (from the animals to the humans to the Tusita Heaven). It is the fruition of great practice, the effects of which shine brightly today as we look to the great disciples for inspiration to keep steady on this Noble Path.
So what does it take to be a great disciple? Following Bhikkhu Bodhi’s account in the introduction to Great Disciples of the Buddha: Their Lives, Their Works, Their Legacy, I lay out the conditions that make possible great discipleship in a specific lifetime, as well as the conditions that make possible the path to great discipleship over many lifetimes. In this account, I find inspiration, commitment, and mystery, all of which can help to keep this path alive for us in each moment.
 I will footnote specific quotes and some specific information throughout this brief essay. However, it should be acknowledged that all detailed information about the Theravādan tradition and the path to great discipleship contained herein comes directly from Bhikkhu Bodhi’s “Editor’s Introduction” in Disciples of the Buddha: Their Lives, Their Works, Their Legacy (hereafter Great Disciples).