The old inconclusive feuds between the two kingdoms were continued between Asa and Baasha. The former is said to have acquired several cities of Ephraim, and to have incorporated them in his own kingdom. In order to secure himself from the attacks of Judah, Baasha seems to have entered into a league with the king of Egypt, and to have urged him to carry war into the lands of his own foe. An Egyptian general named Zerah (Osorkon) sallied forth with a numerous body of Ethiopians, and pressed forwards as far as Mareshah, about ten leagues south-west of Jerusalem. Asa, however, marched against him with the combined forces of Judah and Benjamin, defeated the Ethiopian army north of Mareshah, pursued it as far as Gerar, and brought back enormous booty to Jerusalem.

Baasha was disconcerted by these proceedings, and endeavoured to bring about an alliance with the Aramæan king, Ben-hadad I., of Damascus, who, hitherto friendly to the kingdom of Judah, had prevented all inimical attacks. Ben-hadad, the son of Tabrimon, now cancelled his treaty with Asa, and went over to Baasha's side. The latter conquered Ramah, the birth-place and residence of the prophet Samuel, which belonged to the Benjamites, and fortified it so that it served as a base whence to make raids on the neighbouring districts. Alarmed at these doings, Asa endeavoured to revive the treaty with the king of Damascus, and sent ambassadors to him, with quantities of treasure in silver and gold, which he took both from the Temple and from his palaces. Ben-hadad allowed himself to be won over; it flattered him to be thus sought after by both realms, to which his people had formerly been obliged to pay tribute. He resolved to utilise the weakness of both sides, and he commanded an army to effect an entrance into the north of the kingdom of Israel; he subjugated Ijon, Dan, and the contiguous region of Abel-Bethmaachah; and also reduced the district around the lake of Tiberias, and the mountainous lands of the tribe of Naphtali. Asa was thus saved at the expense of Judah's sister nation; and Baasha was forced to abandon his desire for conquest, and to relinquish Ramah.

Asa now summoned all the men capable of bearing arms to assist in the destruction of the fortifications of Ramah. The death of Baasha, which occurred soon after this (in 933), and a revolution which ensued in Tirzah, left Asa free from menace on that side. Mizpah, a town having a very high and favourable situation, was made an important citadel by Asa. He also built a deep and roomy cistern in the rocks, in order to have stores of water in case of a siege.

Meanwhile, in the kingdom of the Ten Tribes, terrible events were happening, which were productive of changes in both kingdoms. Baasha was succeeded by his son Elah (933–932), who was addicted to idleness and drunkenness. Whilst his warriors were engaged in battle with the Philistines, and were attacking Gibbethon, he passed his days in drinking-bouts. This circumstance was taken advantage of by his servant Simri (Zimri), the commander of one-half of the war-chariots, which had remained behind in Tirzah. Whilst Elah was dissipating in the house of the captain of his palace, Zimri killed him (in 932), at the same time destroying the entire house of Baasha, and not even sparing its friends. He then, as a matter of course, ascended the throne, but his reign was of short duration; it lasted only one week. No sooner had the news of the king's murder reached the army, then besieging Gibbethon, than they elected the Israelitish general Omri, as king. He repaired to the capital, but finding the gates closed against him, he laid siege to the city and effected a breach in the wall. When Zimri discovered that he was lost, he anticipated a disgraceful end by setting fire to the palace and perishing in the flames. He was the third of five kings of Israel who died an unnatural death, and only two of them were buried in the mausoleum for the kings, erected by Jeroboam. A fourth king was soon to be added to the list. Omri, a warrior, expected to obtain the vacant throne forthwith, but he met with opposition. One part of the population of the capital had chosen another king, Tibni, the son of Ginath; he was probably a native of the city. Thus two parties were formed in the capital, and the streets were no doubt deluged with blood. A civil war was the one thing wanting in the domains of Ephraim to make the measure of misery full to overflowing. For three years the partisan conflict raged (932–928); at length the party of Omri gained the upper hand. Tibni was killed, and Omri remained sole ruler (928). He, however, felt ill at ease in Tirzah; the palace was in ashes since the death of Zimri, and other depredations had no doubt taken place during the protracted civil war. The conquered party was hostile to him, and Omri, therefore, determined to transfer the seat of the empire. He could not select Shechem, where the restless and rebellious spirit of the inhabitants would not permit him to live in safety, and there was no other important town situated in the heart of the country. Omri therefore conceived the idea of building a new capital. A high plateau, at a few hours' distance north-west of Shechem, seemed to him the fittest spot. He bought it of its owner, Shemer, erected buildings, a palace and other houses, fortified it, and called it Shomron (Samaria). Whence did he obtain inhabitants for the newly founded city? He probably adopted a course similar to David's in the case of Jerusalem, and caused the warriors attached to his cause to settle there. A year after his victory over the rival king, Omri left Tirzah, and removed to Samaria, which was destined to be the rival of Jerusalem for a period of two hundred years, and then, after two centuries of desertion, to revive, and once more wage war against Judah and Jerusalem. Samaria inherited the hatred of Shechem against Jerusalem, and increased it tenfold. The new city gave its name to the kingdom of the Ten Tribes, and the land was thence called the land of Samaria.

Omri, the first king of Samaria, was neither a strong nor a warlike leader, but he was a wise man. The crown which he had acquired, rather by the favour of circumstances than his own force of will, did not satisfy him. He wished to make his court and his people great, respected and wealthy, and he hoped that the prosperity of the days of Solomon might be restored to Israel. It is true that the nation was divided, and thereby weakened. But was it necessary for war always to be carried on between the two portions, and for the sword to destroy them? Connected as they were by reason of tribal relations and common interests, could they not henceforth pursue their course in friendly alliance?

Omri endeavoured, in the first place, to make peace with the representative of the royal house of David, and to impress upon him the advantages, to both of them, of pursuing an amicable policy. They might in that way obtain their former sway over the countries which had once been tributary to them. For a long time friendly relations were actually established between the two kingdoms; and they supported, instead of opposing, each other. Omri also cherished to a great, perhaps even to a too great degree, the hope of a friendly alliance with Phœnicia. He desired that a part of the riches which their extensive maritime expeditions and trade introduced into that country, might also flow into his own kingdom. At this time various kings had waded to the throne in Tyre through the blood of their predecessors, until at length Ethbaal (Ithobal), a priest of Astarte, ascended the throne, after the murder of his predecessor, Phalles. The disastrous occurrences in Phœnicia had greatly weakened the land. The great families had been compelled to emigrate, and had founded colonies on the north coast of Africa. The kingdom of Damascus, which had acquired great power, sought to obtain possession of the productive coast-line of Phœnicia; Ethbaal, therefore, had to strengthen himself by means of alliances. The kingdom of the Ten Tribes was nearest to him.

Omri and Ethbaal therefore had common interests, and formed an offensive and defensive treaty. The league, desired by both powers, was confirmed by an intermarriage. Omri's son Ahab married Ethbaal's daughter Jezebel (Jezabel or Izebel)—a marriage which was fraught with disastrous consequences.

Omri, fortified by this alliance, could now venture to think of undertaking warlike expeditions. He captured several towns of Moab, which had emancipated itself under Jeroboam's rule, and compelled it to become once more tributary. He forced the Moabites to send herds of oxen and rams every year as tribute. As, however, a sort of alliance existed between Moab and Aram, and an increase of Israel's power was watched by Aram with a jealous eye, the Aramæan king of Damascus, Ben-hadad I., declared war against Omri, and recovered some of the cities he had taken. Omri was forced to accept peace with Ben-hadad on hard terms, and bound himself to open the caravan-roads through the kingdom of Israel, and to allow free passage through the land.

Omri thereupon entered into a closer alliance with the kingdom of Tyre, and pursued the plan of assimilating his people to their Canaanite neighbours. Why should he endeavour to keep Israel separate from the surrounding peoples? Would it not be wiser and better to permit the kingdom of the Ten Tribes to assume a Phœnician or Tyrian character? United as they were in language and customs, might not the two races become more closely welded together, if the Phœnician form of worship were introduced into the kingdom of Israel? Omri led the way to this union. He introduced the service of Baal and Astarte as the official mode of worship; he built a temple for Baal in his capital of Samaria, ordained priests, and commanded that sacrifices should be universally made to the Phœnician idols. He desired to see the worship of the bull, as observed in Bethel and Dan, abolished. It seemed to him too distinctly Israelitish in character, and to be likely to maintain the division between the Israelites and Phœnicians. Jehovah, adored with or without a visible image, was too striking a contrast to the Tyrian Baal or Adonis for Omri to permit His worship to remain. Omri's innovations were of far greater import than those of Jeroboam; or, to speak in the language of the Bible, he acted yet more sinfully than his predecessors. He desired to rob the nation of its God and of its origin; he desired it to forget that it had a special nationality in contradistinction to that of the idolaters. History has not recorded how these changes were received. His son Ahab (922–901) was destined to continue the work,—his father's bequest, as it were. In furtherance of the latter's projects he naturally kept up the close connection with Tyre and with the king of Judah.

But the execution of a charge involving the severest attacks on the inner convictions of man is, in spite of all one may do, dependent on circumstances or contingencies beyond the calculations of the wisest mind. Two kinds of obstacles intervened to prevent the Canaanisation of the Ten Tribes. The one was Ahab's disposition, and the other arose from an unexpected cause which weakened, if it did not entirely destroy, the effect of the terrible blow aimed at religion. In order to accomplish this transformation of the nation into a mere appendage of Phœnicia, and the consequent loss of its own identity, the successor of Omri needed a powerful mind, an unbending will, and unyielding severity to crush all opposition with a strong hand. Ahab was, however, of an entirely different nature—weak, mild, loving peace and comfort, rather disposed to avoid disturbances and obstacles than to seek or remove them. Had it rested with him alone, he would have abandoned his father's system and given himself up to such enjoyments as the royal power granted him, regardless of what the future might bring. Ahab was not even warlike; he permitted the neighbouring kings to treat him in a manner which would have excited the indignation and roused the most determined opposition of any king not altogether destitute of the feeling of honour. But as he was forced against his desire and inclination to enter into a contest with an ambitious neighbour, so he was also compelled to enter upon a conflict with the Israelitish nation. His father had given him a wife in every way his opposite, with a strong manly will, who was determined to gain her ends by severity and cruelty, if necessary.