The Buddha of the Great Canon expounds The Mahayana Sutra on Repaying Kindness

Thus have I heard: Once the Buddha was on Vulture Peak, surrounded by the Great Assembly. At that time, Ananda entered the city to beg for food. In the city there was a man who tended filially to his parents; their property having been lost to them, he carried his parents on his shoulders as he went about begging. All the good food he offered to his parents while he himself ate that which was disgusting. Ananda praised the man for supporting his parents, (at that) time such a person being extremely difficult (to find).

There happened by six masters and disciples, holders of heretical ideas, who had savagely burned the True Law, and whose hearts harbored envy. To Ananda they said, “Your master of the Shakya clan proclaims himself to be a person of excellence, endowed with great merit. But his is a hollow name with no basis in actual practice. He has set aside his parents to leave the city, not knowing the kindness he has (personally) received from them. This is not a filial person.”

When Ananda heard this, in his heart he felt ashamed. Returning to the Buddha he asked, “Within the Buddha’s Law, why] isn’t there a bias toward filial support for parents?” The Buddha replied, “Who instructed you to ask this?” Ananda said, “While begging for food, I came upon six masters and disciples, and saw them slandering by such as I have stated above.” The World-Honored One let out a little smile, emitting a five-colored light that reached all of the Buddhas of the Ten Directions. The bodhisattvas of those lands together intoned, “What causes this radiance?” The Buddhas of those lands replied, “In the Saha realm, there is a Buddha named Shakyamuni who to the multitude is expounding The Mahayana Sutra for Repaying Kindness desiring to cause all creatures to be filial and caring toward their fathers and mothers; as such he releases this radiance.”

At that time, upon the Buddha’s body appeared the five forms of reincarnation and one-by-one within these forms appeared limitless small worlds, so numerous that their forms and characteristics were beyond thought or description, one body corresponding to (each of) the myriad beings with enough so that all receives a body. It is because of the receiving of a body that all the myriad creatures were once the parents of the Buddha, and moreover, that the Buddha once was the parent of every sentient being. Therefore, he (Shakyamuni as a bodhisattva) constantly cultivated difficult practices, undertaking painful austerities so difficult to practice that he was able to renounce what is difficult to renounce. Diligently keeping up his perseverance, he perfected the 10,000 practices, never resting, never growing weary at heart. It is because of one’s (efforts) to teach and nurture one’s father and mother that one is able to quickly become a celestial Bodhisattva. (All this) is due to the virtue of being filial.

大藏佛说《大方便报恩经》 如是我闻，一时佛在耆阇崌山中，大众围绕。时阿难入城乞食。城中有一男子，孝养父母，家□荡尽，担父母行乞，好者奉亲，恶者自食。阿难偈语赞男子供养父母，□时难及。有六师徒，执着邪论，残灭正法，心怀嫉妒，语阿难曰：汝师释种，自言善好，有大德，唯有空名，而无实行，舍父母出城，不知恩分，是不孝人。阿难闻已，心怀惭愧，诣佛白言：佛法中颇有孝养父母不？佛言：谁教汝问？阿难言：乞食逢六师徒，见毁骂辱，如上所陈。世尊微笑，放五色光，至十方如来所。彼国菩萨同音‘何缘有此光明’？彼国佛言：有娑婆界佛号释迦，为大众说《大方便报恩经》，欲令众生孝养父母，故放斯光明。尔时，如来身中现五趣身，一一身中现无量微尘数不思议形相，一切众生具足受身。以受身故，一切众生曾为如来父母，如来亦曾为众生作父母。故常修难行、苦行、难舍、能舍，勤修精进，具足万行，不休不息，心无疲倦，为教养父母故，令得速成天上菩萨，由孝德也。