I caution you on your wording. Congress did not authorize him to do so, but rather indemnified him for having done so.
The difference may be slight, but whenever I'm inexact in my phraseology (sp?), I'm made to pay for it later.
Here is part of the wording of the 1863 act:
"AN ACT relating to habeas corpus, and regulating judicial proceedings in certain cases. Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That, during the present rebellion, the President of the United States, whenever, in his judgment, the public safety may require it, is authorized to suspend the privilege of the writ of habeas corpus in any case throughout the United States, or any part thereof."