أن الجنابة لا تنافي الصوم
Major ritual impurity is not in itself incompatible with the fast.
If the fasting day can validly begin while the person requires ghusl, the mere persistence of that state does not by itself invalidate fasting. This distinguishes an initial condition from its continuation.
The reasoning also clarifies involuntary nocturnal emission, which is not treated like a deliberate act of breaking the fast during the day. The discussion also considers cupping and applying oil by distinguishing such acts from what actually contradicts the fast.
It would be incorrect to infer that bathing is unnecessary. Ghusl remains required for acts such as prayer; the point is that a delay in bathing is not itself a cause of an invalid fast.