Sefer HaBahir 80

1[The students asked,] "But why (WHAT IS?) Zayin"?[Rabbi Rachumai responded,] "As it is written in ear (WAS THIS IN THE QUESTION OR ANSWER? KAPLAN SAYS IT'S IN Q]. That we have said, all that the Blessed Holy One brings into His world, its name is from its essence, as is written, 'Whatever the Adam called each living creature [נפש חיה], that was its name' (Genesis 2:19) — that is to say, its body was thus. Where do we learn that one's name becomes its body? As is written, 'The name of a righteous person is invoked in blessing, but the name of the wicked rots' (Proverbs 10:7). Does a name rot?* Rather, it means the body. Here too, [it means] his body."*Manuscripts read מרקב as opposed to ירקב.