Done well Jackson was a great Civil War genetal.
In this case, though, he went out at night to try and assess Union positions. He did not tell anyone he was leaving or where he was going. No one could have known it was Jackson before they fired.
The Confederate infantry in the area had been warned earlier to be on the lookout for Union cavalry. Jackson was riding with several men of his staff when they were challenged, then fired on, before being able to reply.
Jackson may not be the hero he’s often perceived as. His nickname — Stonewall — may not have been a compliment. It was given to him by Gen. Barnard Bee at First Bull Run, who observed him “standing like a stone wall.” The problem was, Jackson was supposed to be advancing.
The intent of Gen. Bee’s words has been fiercely debated over the years. Personally, I find Longstreet a better exemplar.