After the heavy losses taken at Dan, 'Ah'ab and his 2,000 or so remaining men retreat north-west across the Yarden Valley, hoping to reach the Litanu River and follow it to the coast; While it would have been much faster to retreat south-west back towards Samaria, such a movement would have brought the Ba'alists directly through the lands of the tribes of Naptali and Zevulun, who were both very warlike and very Y----ist. Unwilling to risk being trapped in some waterless valley by the aforementioned tribesmen, 'Ah'ab would instead play it safe. This, however, would be do his undoing.
However, it would not come from the obvious quarter, as Yehu didn't move to pursue him. Instead, he demanded the surrender of Dan's elders, who quickly accepted after seeing their relief force routed beneath their walls. Yehu subjected the city to three days of sacking, ordering both the altars of the Baals and their attendants to be crushed under the hooves of oxen (After stripping them of their precious metal, of course). He then marches south-west, where he finds the ~1500 or so remaining Numidians camped on the slops of Mt. Odem, a day's ride from Dan. Yehu surrounds them and issues an ultimatum: either join him, at 3/4 of their previous rate or die. The Numidians, both surrounded and far from home, agree.
He then sends out riders to the elders of Naptali and Zevulun, asking them to join him overthrowing the infidel king. At the same time, he sends a rider to Ber-Hadad of Dammesq, offering a tribute of 100 talents of silver per year upon his installation in exchange for non-interference. Ber-Hadad agrees, but it is not the tribute that stays his hand, but rather the presence of the Y----ist army at Dan; It would be both easier and safer to wait to move on before invading.
The leaders of the two aforementioned tribes eagerly agreed, Naptali raising 4,000 light and 2,000 heavy infantry and Zevulun raising 1,000 light and 500 heavy. These forces camp on the plain of Kinnereth, on the north-western shore of the Sea of Galilee. Yehu joins them in early 880, creating a Y----ist host composed of 6,000 light infantry, 4,500 heavy, and and 1,500 cavalry. He spent that year criss-crossing the plains north of the sea, subjecting the Y----ist cities to his rule and the Baalist cities to tribute. In the fall of 880, he also accepted the submission of the tribe of Yissakar, to the south of the sea.
However, neither 'Ah'ab or Ber-Hadad spent the year idle. The former returned to Sham'on in spring 880, where he set about raising another host. He gathered 8,000 light and 5,000 heavy infantry from the lands of Mahnashe, 2,000 light from Dan and 1,000 light from Binyaamen, 1,000 heavy from Efrayim, by the end of 880. He gathered this host together and wintered at Beth Shahan, on the border with Yissakar. 'Ah'ab also sent messengers to Ber-Hadad, asking him to invade the lands held by Yehu in exchange for a payment of 1,000 talents of silver. Ber-Hadad, already planning an invasion, readily agreed.
As for Ber-Hadad, he had raised a force of 9,000 light infantry, 5,000 heavy infantry, and 3,000 cavalry and wintered at the town of Edre'i, southwest of the Sea of Galilee. From this location, he could turn against either 'Ah'ab or Yehu. However, he decided that it would be best to strike at Yehu, crush him quickly, then turn and assault 'Ah'ab to force him to pay tribute. In spring 879, he crossed the border and marched towards the Sea of Galilee.
Yehu had wintered at Gad'ara, just north of where the Yarmuk flows into the Yarden, with his entire force. As such, when news of Ber-Hadad's invasion reached him, he marched east to meet him. However, upon seeing the size of the Dammesqian army, Yehu instead turned and retreated to the heights of the left bank of the Yarmuk, predicting that the Dammesqians would follow the river into the flat-lands of the Yarden valley. He was correct, and as the invaders advanced along the river they came under bombardment from the slings and bows of the Y----ist skirmishers. This caused some losses amongst the Dammesqians, but the primary effect was to enrage them and make them eager for blood. As the Dammesqians advanced, Yehu began to realize that they would not turn back before reaching the lowlands, and so ordered his heavy infantry to form up at the very edge of the heights, where the exit was less than half a mile wide. However, the initial, enraged Dammesqian charge broke through the first Y----ist line and caused the lines behind that to fall back; had it not been for a fortuitous sand-storm rolling in off of the hills, the Dammesqians likely could have routed Yehu's men; However, with this seemingly divine shield, Yehu was able to fall back four miles to the small town Matzada, where he reorganized his force and set them into battle formation.
