注大乘入楞伽經 6.9

6.9

法身者知二無我等法名法身；色身者相好莊嚴名色身。佛佛皆無差別，除為調伏彼彼諸趣差別眾生，示現種種異類色身。此正答何妨是佛，及百千種類受生，是名身等無有相違。

The dharmakāya: knowing dharmas such as the two kinds of selflessness is called the dharmakāya; the rūpakāya: the adornment of major marks and minor signs is called the rūpakāya. Between Buddha and Buddha there is no difference, except for manifesting various types of physical bodies to subdue different sentient beings in various realms. This directly answers how there is no contradiction between being the Buddha and undergoing births in hundreds of thousands of forms; this is called equality of body, free of contradiction.