structural:expansion, structural:summarization, structural:scholar_edition
Background

According to Buddhist texts, when a fully enlightened Buddha appears in the world, he always has a set of chief disciples. For the current Buddha, Gautama, his chief male disciples were Śāriputra and Maudgalyāyana, while his chief female disciples were Khema and Uppalavanna. According to the Buddhavaṃsa, all Buddhas of the past followed this pattern of selecting two chief male disciples and two chief female disciples. German Buddhist scholar and monk Nyanaponika Thera states that the reason Buddhas always select two chief disciples is to balance responsibilities according to each disciple's specific skills.

According to the Pāli Canon, in the distant past Śāriputra was born a wealthy person named Sarada who gave away his wealth to become an ascetic who developed a large following. At that time, Sarada and his followers were visited by the past Buddha, Anomadassi Buddha, and were given a sermon by Anomadassī Buddha and his chief disciples. Upon hearing the sermon from Anomadassī Buddha's first chief disciple Nisabha, Sarada became inspired and resolved to become the first chief disciple of a future Buddha. He then made this wish in front of Anomadassī Buddha, who looked into the future and then declared that his aspiration would come true. Upon hearing the prediction, Sarada went to his close friend Sirivaddhana and asked him to resolve to become the second chief disciple of the same Buddha. Sirivaddhana then made a large offering to Anomadassī Buddha and his following, making the wish as suggested. Anomadassī Buddha looked into the future and declared that Sirivaddhana's aspiration would also come true. The two friends then spent the rest of their lives and many future lives doing good deeds. According to Buddhist legend, the aspiration came true in the time of Gautama Buddha with Sarada being reborn as Śāriputra and Sirivaddhana as Maudgalyāyana.