A union of the two kingdoms was distasteful to both. The difference in their history prevented their coalescing. The house of Israel, especially the tribe of Ephraim, willingly relinquished the advantages which might accrue from a union with the house of David, in order that it might not be forced to assume an inferior position. The more worthy in both kingdoms were probably filled with grief at the breach which had occurred, but they were unable to avert it. The civil war which appeared imminent was prevented by the prophet Shemaiah, who, in the name of God, called on the Judæans and Benjamites to desist from fratricide. Slight feuds, however, broke out between the contiguous kingdoms, as was unavoidable between such near neighbours, but they led to no serious result.
Jeroboam was effectually aided in his ambitious plans by Shishak (Sheshenk), who, it is said, married his wife's elder sister Ano to the fugitive Israelite, just as he had given another sister in marriage to the Idumæan prince who had taken refuge with him. Shishak probably had furnished Jeroboam with the supplies of money that enabled him to return to his fatherland, and now the new king seems to have formed an alliance with him against Judah. Thus Rehoboam was prevented from undertaking any noteworthy steps against Israel. In order to secure himself from Egyptian and Israelitish attacks, Rehoboam erected a chain of fortresses in a circuit of several miles round about the capital. But they failed him in the hour of need. Shishak, with an overwhelming force, undertook a war against Rehoboam in the fifth year of the Jewish king's reign (972). Overcome by excess of numbers, the strongholds were taken one after another by the Egyptian armies, and Shishak pressed forward as far as Jerusalem. It appears that the capital yielded without a struggle, and the Egyptian king contented himself with seizing the treasures which Solomon had deposited in the palace and the Temple. He appropriated all the money then in Jerusalem, as well as the golden shields and spears which the king's guards used in royal processions to the Temple. He, however, left the kingdom of Judah intact, did not even touch the walls of Jerusalem, and left Rehoboam on his throne. On his return, Shishak commemorated his deeds of prowess and his victories over Judah and other districts by records and monuments. The alliance between Solomon and the king of Egypt was thus of but short duration. His son learned the futility of such a treaty, and experienced how little trust can be placed in plans and political measures, though apparently the outcome of the deepest calculation and forethought. Solomon, in spite of his wisdom, had acted thoughtlessly in regard to the union with the daughter of Pharaoh. He had built her a special palace, and within a few years after his decease, an Egyptian king ransacked this very palace and other monumental buildings of Solomon, and plundered them of all their treasures. The grandeur and power of Solomon's kingdom were at an end.
Jeroboam fortified Shechem and built himself a palace, which served also as a citadel (Armon) for purposes of defence. On the opposite side of the Jordan, he also fortified various towns, among them Penuel (or Peniel), to serve as a rampart against attacks from the south, where the Moabites and the Ammonites, in consequence of what had taken place, had separated themselves from the Israelites, in the same way as the Idumæans had shaken off the yoke of the Judæans. Internal embarrassments forced Jeroboam to introduce innovations. Guided either by habit or conviction, the families of the northern tribes continued to present themselves at Jerusalem in the autumn at harvest time, in order to take part in the service of the invisible God. This loyalty to the Jewish capital, even though manifested by only a part of his subjects, was a source of great anxiety to Jeroboam. How would it be if the people turned in ever increasing numbers to the temple in Jerusalem, and once more made peace with the house of David? Would he not be dethroned as quickly as he had attained to royalty? In order to avoid the possibility of such a reunion, Jeroboam matured a wicked plan, which caused Israel to fall back into the ways of idolatry and barbarity.
During his protracted stay in Egypt, Jeroboam had become acquainted with the system of worship established there, and he had observed that the worship of animals, particularly of the bull, tended to promote the aims of despotic government. He had observed that this animal worship served to stultify the nation, and Jeroboam thought he might turn to his own purposes a system so politic and advantageous. He therefore, in conjunction with his advisers, devised a plan by which these observances should be introduced in the Ten Tribes. He considered that this idol-worship might be of advantage to him in other ways, as it would keep him in favour with the court of Egypt. Israel would appear as a dependency of Egypt, and both countries, having common religious observances and customs, would also have common interests. The habits of Egypt were of special interest to him, as his wife was probably an Egyptian, and connected with the royal house of Egypt. Jeroboam also studied the convenience of the tribes. He wished to relieve those who lived far off from the necessity of making long journeys at the time of the harvest. At Bethel and at Dan, Jeroboam, therefore, put up golden calves, and issued a proclamation to the effect: "This is thy God, O Israel, who brought thee out of Egypt." In Bethel, where he himself intended to preside at the worship, he built a large temple, in which he also placed a sacrificial altar. To prevent the people from celebrating the Feast of Ingathering at Jerusalem, he fixed the festival a month later (in the eighth instead of the seventh month). Probably also a different time-reckoning was followed, according to the longer solar, instead of the shorter lunar year.
The nation, as a whole, appears to have taken no offence at this alteration, but to have actually regarded it as a revival of the ancient mode of worship. The fundamental principle, the unity of God, was in no way affected by it. Jeroboam had not attempted to introduce polytheism, but had merely given them incarnations of the Deity, symbolising strength and fruitfulness. The people, naturally sensual, were, indeed, well pleased to have a representation of the Godhead. The spirituality of God, not admitting of ocular demonstration, was at that period more remote from their comprehension than the conception of His unity. Sensual dissipation and depravity were not bound up with the worship of the bull as with the Canaanite service of Baal, and therefore it did not outrage the moral sense.
Thus the people gradually became accustomed to repair to Bethel or Dan for the high feasts; otherwise they made their offerings at home, or at the nearest place where sacrifices had been offered of old. Jeroboam fully attained his object; the nation became stultified, and bowed to him in servile obedience. The tribe of Levi, however, caused him anxiety. No Levite would consent to perform the office of priest at the worship of the bull; for Samuel's prophetic teachings had made a lasting impression on this tribe. That Jeroboam might not compel their services, the Levites, who had been living in the Israelitish towns, wandered forth, and settled in the kingdom of Judah. As he could not possibly manage without priests, he took any one who offered himself to serve in that capacity. At one festival he himself performed the priestly office, in order to elevate it in the eyes of the people, or, perhaps, in imitation of the Egyptian custom. Jeroboam was thus led step by step to destroy the original principles of Judaism.
His conduct was not allowed to pass uncondemned. The old prophet, Ahijah, of Shiloh, who had incited Nebat's ambitious son to insurrection, now was too old and frail to lift his voice publicly against these proceedings. When, however, Jeroboam's wife visited him at Shiloh, to consult him about the dangerous illness of her eldest son, the prophet took the opportunity of announcing to her the approaching dissolution of the royal house. But a return was impossible, without paving the way to a reunion with the house of David. From motives of self-preservation, he was obliged to continue in the way he had chosen. The new worship was, therefore, retained during the existence of the kingdom of the Ten Tribes, and none of Jeroboam's successors attempted to make any alteration in its form.
In the kingdom of Judah (or House of Jacob), the conditions were quite different. Politically weakened by the severance of the tribes and the incursions of Egypt under Shishak, its wounds were too deep to heal before the lapse of a considerable time. But Judah had not sunk in religion or morals. Rehoboam appears to have troubled himself but little about religious or moral affairs; he was indifferent in every respect, and his pride having once received a blow, he seems to have passed his days in idleness. But the Temple, on the one hand, and the Levites, on the other, appear to have counteracted all deteriorating influences. In outward appearance all remained as it had been in the time of Solomon; the High Altars (Bamoth), on which families performed the sacrificial rites throughout the year, continued to be maintained, but at the autumn festivals the people repaired to the temple. Deviations from the established order of divine service were exceptional, and were accepted only by the circle of court ladies. As Solomon had permitted altars to be erected for his heathen wives, Rehoboam did not feel called upon to be more severe in his enactments. His mother Maachah, the daughter or granddaughter of Absalom, had a predilection for the immoral Canaanite worship; she erected a statue of Astarte in her palace, and maintained temple priestesses. Rehoboam permitted all this, but the unholy innovations did not spread very wide. Meanwhile, although idolatrous practices did not gain ground in the kingdom of Judah, there was no impulse towards a higher stage of moral culture under Rehoboam's government. A weakness seemed to have come over the people, as if they were in the last stage of senility. Nearly two centuries elapsed before traces of a higher spiritual force became evident. Rehoboam's reign of seventeen years was inglorious. The reign of his son Abijam (960–958) passed in a like manner. He also indulged in petty acts of hostility against Jeroboam, but without any important result. He, too, permitted the idolatrous practices of his mother Maachah. Abijam, it appears, died young, leaving no issue, and he was therefore succeeded by his brother Asa (957–918). He again was a minor, and the queen-mother Maachah held the reins of government. At first she seems to have desired to extend her idolatrous and immoral worship, but a revolution in the kingdom of the Ten Tribes put an end to her projects, and changed the course of events.
Nadab, who had succeeded to the throne on the death of Jeroboam (955–954), undertook a war against the Philistines, and besieged the Danite city of Gibbethon, which the Philistines had occupied. During this campaign a soldier by the name of Baesha (Baasha) conspired against the king in the camp, and killed him. From the camp Baasha proceeded to the capital, Tirzah, and destroyed the whole house of Jeroboam (954). The founder of this dynasty had not been anointed by the prophet; he was not considered inviolable, like Saul and David, and therefore the hand of the murderer was not restrained. Baasha was the first of the list of regicides in the Ten Tribes, and his act hastened the fate impending over the nation.
Having perpetrated the murder, he took possession of the throne and kingdom (954–933). He continued Tirzah as the capital, on account of its central position. It lay in the very heart of the kingdom, and possessed the additional advantage of being fortified. Had Baasha abolished the worship of the bull, he might have drawn to his side the worthier portion of the people of Judah. The latter were indignant at the idolatrous innovations of Maachah, which were more reprehensible than the bull-worship, as with them were connected the depraved habits of the temple priestesses. In Jerusalem the fear of eventual sympathy with Israel appears to have arisen; but Asa hastened to avert the calamity. Either on his own impulse, or urged thereto by one of the prophets, he snatched the reins of government from the hands of the queen-mother, forbade the worship of Astarte, removed the priestesses, and burnt the disgusting image which had been erected for worship in the valley of Kedron. Through these resolute acts Asa secured for himself the good-will of the well-disposed among his people.