First, you'll need to find the User who is logging in based on email address or username or however you identify them, for example:
$user = User::where('email', '=', 'firstname.lastname@example.org')->first();
Then, you'll need to CHECK the hashed password, like so:
Hash::check('INPUT PASSWORD', $user->password);
This will return true or false based on whether or not the password matches.
Hope it helps!!