Git revert back to a certain commit

I want to revert my code back to a certain commit. I do not want the changes to stay either.
This is the commit id which I want to go back to.

a7f9f64c2df1b6133656955f9049d68d6e8cd261

>Solution :

This code will permanently undo all your changes after this commit.

git reset --hard a7f9f64c2df1b6133656955f9049d68d6e8cd261