You're doing the following:

1. Fetching a user from the database
2. Assigning their username and hashed password to variables
3. Attempting to log the user in using their hashed password

However that won't work because...

attempt takes a username (eg: admin) and a plain text password (eg: 123). The user database stores the hashed password (eg: $2a$10$xbFFpiHRRv8y6e.6STPQxehcLwY8V9Lq/HUNjfbuCdHSe2PTLBcNy) which means you're passing the hashed password to attempt, which will always fail.

If you want to login a user by their ID (eg: 1) use loginUsingId:

Auth::loginUsingId(1);

If you want to login a user using a provided username and password use attempt, eg:

$username = 'admin';
$password = '123';
Auth::attempt(['username' => $username, 'password' => $password]);

http://laravel.com/docs/security#authenticating-users