'show' pretty %B without a diff

Hey Mr(s) git show some good to me!

I'd like to output a comment in my script.
Thus, I try: 'git show --format="%B" commitId'
There is always diff in the end of the output. No matter what format I specify, even when it is empty.
How can I avoid diff output in the 'git show'?
Thank you.

73! Peter pgp: A0E26627 (4A42 6841 2871 5EA7 52AB  12F8 0CE1 4AAC A0E2 6627)
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