YOU SAID:

the spirit is willing bit the flesh is weak

INTO JAPANESE

精神は喜んで噛むが、肉体は弱い

BACK INTO ENGLISH

The spirit is willing to bite, but the body is weak.

INTO JAPANESE

精神は喜んで噛みつきますが、体は弱いです。

BACK INTO ENGLISH

The spirit is willing to bite, but the body is weak.