What is the difference between saving and committing a config?

• Palo Alto Firewall or Panorama
• PAN-OS 

1. Saving a config change is basically saving the xml configuration to a file.  Although the configuration is saved, the changes done is not effective till commit operation is completed.
2. Saving the configuration does not apply the changes into the current config. To apply the change, one must "commit" the configuration.
3. A commit is the process of activating the changes to the firewall configuration.

For more details Refer to:

• Commit, Validate, and Preview Firewall Configuration Changes
• Save and Export Firewall Configurations

After commit,  If the changes done to the configuration are causing problem, one can revert to the previous configuration using the method below.

• Go to GUI: Device > Setup > Operations.
• Click on  Load config version.
• Use the drop down menu and verify the timestamp when the last commit was done is displayed.
• Select the previous config than the most recent changed one and click OK.
• Once loaded, "commit" the configuration