I think, bwawok's answer is wrong at some point:
if you do
git reset --soft c14809fa
It will make your local files changed to be like they were then, but leave your history etc. the same.
According to manual: git-reset, "git reset --soft"...
does not touch the index file nor the working tree at all (but resets the head to <commit>, just like all modes do). This leaves all your changed files "Changes to be committed", as git status would put it.
So it will "remove" newer commits from the branch. This means, after looking at your old code, you cannot go to the newest commit in this branch again, easily. So it does the opposide as described by bwawok: Local files are not changed (they look exactly as before "git reset --soft"), but the history is modified (branch is truncated after the specified commit).
The command for bwawok's answer might be:
git checkout <commit>
You can use this to peek at old revision: How did my code look yesterday?
(I know, I should put this in comments to this answer, but stackoverflow does not allow me to do so! My reputation is too low.)