Git, comparing a file with a different commit

Hello!

I have a file.
For example 'bla.php' .

In the version management I have this file in a previous commit.
The hash value of this commit is known to me.

Can I perform a comparison of the current file with the file of the previous commit?

Where can I enter the known hash value for git ?

Sorry for my bad english.

Sincerely yours

Stephan