מלכים ב, פרק י״ז, פסוק ה׳

The Assyrian military campaign against Israel was a sweeping offensive that engulfed the surrounding territories before striking the heart of the kingdom. The king of Assyria launched his attack with the clear goal of conquering the entire land of Israel [מצודת דוד, ביאור שטיינזלץ]. Rather than marching directly on the capital, his forces first swept through and captured the rest of the region. Only after successfully securing the broader territory did the Assyrian army turn its full attention toward the capital city of Samaria [רד״ק].

Upon reaching Samaria, the invading forces surrounded the city and placed it under a heavy siege [מצודת ציון]. This blockade dragged on for three long years. Such a lengthy standoff is especially notable because the capital had already been left without its king. The fact that the city held out for so long under these desperate conditions shows that Samaria put up a fierce resistance and did not surrender easily [ביאור שטיינזלץ].