need help translating a phrase

I encountered this while reading a manga. I included the kanji for the words I am not sure about. Even after looking them up on denshi jisho, i'm not sure how they fit in with the meaning of the sentence as a whole.
ayamachi wa hito no ayumi wo tomeru kase ni arazu. kokoro wo sodateru (育てる) kate(糧) de aru.
I know what the individual words mean, but I am having trouble piecing them together. what i have for a very rough translation so far is:
The mistake isn't the shackles that hold people back. It's the (provisions?) of the maturing heart.

Can someone help me fix my translation?
Thanks in advance.

心を育てる糧である。
It's nourishment to mature one's heart.

As you might notice, kase and kate rhyme.

that makes a lot more sense now. i couldn't think of the right word to translate it with. thanks!