《礼记·郊特牲》
从这上面可以看出祭祀天神和祭祀人鬼是有区别的 世上的万物都是天生的，世上的人也都是老祖宗一代一代传下来的，这就是祭天时为什么要让始祖配享的原因。郊天之祭，就是一次对天对始祖的普遍回报。
所以别事天神与人鬼也。万物本乎天，人本乎祖，此所以配上帝也。郊之祭也，大报本反始也。
One can see from this that there is a difference between sacrificing to Heaven and sacrificing to ghosts and spirits. All myriad things are generated by Heaven, and humans are descended from their ancestors. This is why the first ancestors were included in sacrificial offerings to Heaven. The Suburban Sacrifice is a general requital to Heaven and the first ancestors.