Nevertheless, coming to the Lotus Sūtra, which enjoins listeners to “abandon the expedient teachings,” Maudgalyāyana immediately cast away the 250 precepts of Hinayāna Buddhism and chanted “Namu Myōhō Renge Kyō” to become a Buddha called Tamālapatracandana Fragrance. This is the very moment when his parents, too, became Buddhas. Therefore, it is stated in the Lotus Sūtra, “Our wishes have already been fulfilled, and desires of the multitude are also satisfied.” Maudgalyāyana’s body and mind are the legacy of his parents. When his body and mind became a Buddha, those of his parents also attained Buddhahood.
Urabon Gosho, On the Ullambana Service