法苑珠林 50.8

50.8

又大般若經（第四百四十三云）若有問言。誰是知恩能報恩者。應正答言。佛是知恩能報恩者。何以故。一切世間知恩報恩無過佛故。

Furthermore, the Mahāprajñāpāramitā-sūtra (fascicle 443) says: 'If someone asks: "Who knows kindness and is able to repay kindness?" one should rightly answer: "The Buddha is the one who knows kindness and is able to repay kindness." Why is that? Because in all the world, no one surpasses the Buddha in knowing kindness and repaying kindness.'