"Six at the Beginning: the army sets forth with discipline... if it is not good, there is misfortune."
Correct meaning: "Six at the Beginning: the army sets forth with discipline"—discipline means law and regulation. Six at the Beginning is the start of the army, the one that marshals the multitude.
Having marshaled the host, when the army sets forth, it must be aligned with legal discipline; hence it says "the army sets forth with discipline."
"If it is not good, there is misfortune": if discipline is lost in moving the army, whether in defeat or in success, all ends in misfortune. "Not" refers to defeat and ruin; "good" refers to having merit and success.
Yet since defeat is itself misfortune, why add "whether bad or good, there is misfortune"? The original intent is to make clear that even success without discipline is misfortune.
Because "good" standing alone would be abrupt, "bad" is paired with it, emphasizing that even apparent success is calamitous, which could not be adequately expressed by mentioning success alone; hence it says whether bad or good, both are misfortune.
Commentary: From "Being the beginning of the army" to "both lead to misfortune."
Correct meaning: "Being the beginning of the army, it is the one that brings order to the host"—being the first line of the Army, it is called the beginning of the army. Standing at the head of the army and sounding the first initiative, it marshals the multitude.
"If discipline is lost yet some success is had, how does that differ from failure?"—if laws are cast aside and not followed, even if merit is won and deemed good, how is it any different from failure?
"When orders are violated to gain merit, military law allows no pardon" explains the meaning of "how does it differ from failure." Orders are laws and commands.
If one violates these commands, even if meritorious service is achieved, military law permits no pardon; hence it is asked, "how does it differ from failure?"
Yet matters beyond the borders are entrusted to the general to adapt to circumstances, not needing to adhere blindly to the sovereign's command in every detail. Why then is gaining merit said to be "unpardonable by law"?
In conducting an army, circumstances are manifold; weighing matters, adapting to necessity, advancing or retreating according to the moment—these fall under the general's discretion.
But if one indulges private whims, deliberately defies the sovereign's mandate, and breaches laws and discipline, then the offense cannot be pardoned.