Custom Drush command and Settigns::get(), Config::get() how can I access site configuration when in Drush command?

Global variable $config === null and when I use Config::get('key'), I get


  Error: Using $this when not in object context in Drupal\Core\Config\Config::get() (line 85 of /var/www/drupalvm/drupal/web/core/lib/Drupal/Core/Config/Config.php)`


What is the recommended approach? I can't find it anywhere... thank you!

Edit

I actually intended to access Settings, not Config - that's where the confusion came from. Settings::get() works just fine. To get data from config, just follow the accepted answer.
Get is not a static method, so it should not be called statically (using ::). Use Drupal's service container and get the config service using \Drupal::service('config'), then get your config from that.