דברי הימים א, פרק כ״א, פסוק ז׳

Counting the members of a nation is a sensitive action that carries severe spiritual weight. In this instance, the census triggers strict divine judgment, ultimately bringing harm to the people. God became deeply angry because the count was carried out without the Israelites providing the required ransom for their souls [מצודת דוד].

As a result, a severe blow was dealt to the nation, though there are different perspectives on exactly when and how this punishment unfolded. One approach suggests that an illness or plague immediately began to spread among the people at this early stage [מלבי״ם, ביאור שטיינזלץ]. Conversely, another perspective maintains that the actual plague did not strike until later. According to this view, the punishment only occurred after God presented David with different options for a penalty, and David chose to place himself directly into His hands [מצודת דוד, רלב״ג].