God issues a firm oath to emphasize the absolute certainty of an approaching historical shift. To illustrate the power of this divine decree, the imagery relies on Tabor and Carmel, two widely recognized and famous mountains [מצודת ציון]. The primary approach among commentators is that these mountains symbolize permanence, stability, and undeniable truth. Just as Mount Tabor is firmly planted in the earth and Mount Carmel stands securely on the coast without ever moving, the arrival of Nebuchadnezzar, the king of Babylon, into Egypt is an absolute reality that cannot be altered or stopped [רש״י, מצודת דוד, רד״ק].
Building on this idea, the imagery also highlights the striking visibility of these mountains. The fate of the Egyptians is as clear and obvious as Mount Tabor, which stands out sharply against its surroundings despite not being exceptionally tall, and as Mount Carmel, which is highly noticeable as it extends directly to the sea [ביאור שטיינזלץ]. Taking an allegorical path, other interpretations view the mountains as symbols of hunting and exile. Mount Tabor was known as a place where hunters spread nets to catch birds, mirroring how the Egyptians will be hunted down. Similarly, the reference to Carmel by the sea represents the trees of the Carmel forest being cut down and carried away by ships, painting a clear picture of the Egyptians being taken into captivity and exile [רד״ק, צאינה וראינה].
A completely different perspective shifts the focus away from the enemy's certain arrival or the resulting exile, viewing the mountain imagery instead as a symbol of physical paralysis. Just as God permanently fixed Mount Tabor among the mountains and Mount Carmel by the sea so they can never cross their borders or move, the same applies to Pharaoh, the king of Egypt. Despite being close to the battlefield, he will remain entirely stationary, unable to leave his place or join the fight [מלבי״ם].