《列子·天瑞》
后稷因为母亲踏了天帝的足迹而诞生，伊尹因为母亲梦遇神仙而生于空桑。
后稷生乎巨迹，伊尹生乎空桑。
Hou Ji was born because his mother stepped on the footprints of the Heavenly Emperor; Yi Yin was born in Kong Sang because his mother dreamed of a fairy.