Surah 19. Maryam, Ayah 97

Since man is incapable of understanding the "word" of God as such, it has always been revealed to him in his own, human tongue (cf. 14:4 -"never have We sent forth any apostle otherwise than [with a message] in his own people's tongue"), and has always been expounded in concepts accessible to the human mind: hence the reference to the Prophet's revelations as "brought down upon thy heart" ({2: 97}), or "[divine inspiration] has alighted with it upon thy heart" ({26: 193-194}).