Abijah generally did not please God (1 Kings 15:3). However there was the instance the Chronicler recorded in which he spoke out in favor of the temple, the priests, and the Levites against the apostate Jeroboam and Israel.
This is the only place in Chronicles where the writer linked the reigns of the southern and northern kings (vv. 1-2). He may have done this to identify the occasion on which Abijah made his speech since Jeroboam and he were constantly fighting. Abijah took the offensive this time even though Jeroboam outnumbered him two soldiers to one (v. 3). Abijah charged Israel with fighting against Yahweh since the Judahites had remained faithful to Him (vv. 11-12). Judah won because the people relied on Yahweh (vv. 15, 18).
"It is hard to avoid the thought that, in biblical theology, weakness is a positive advantage, because it is a prerequisite of reliance (cf. 2 Cor. 12:10)."33
The reference to a "covenant of salt"(v. 5) suggests the connection between the ratification of a treaty and a meal (Exod. 24:11) at which salt provided seasoning (cf. Lev. 2:13). Normally participants sealed covenants by eating a meal together. What is more important, salt as a preservative symbolized the covenant makers' hope that their agreement would last a long time (cf. Num. 18:19).
The real difference between the Southern and Northern Kingdoms was theological. Judah was relying on what God had done, but Israel was trusting in what she could do. The temple site and ritual were God's provision for His people (cf. Gen. 22:14). Israel had rejected these and had set up a system of her own devising that she hoped would make her acceptable to God. Israel had rejected God's grace and had adopted a works system of worship.
This chapter is the only assessment in Chronicles of the Northern Kingdom's sin. From here on, the writer's attention focused on Judah primarily.
Other evidences of God's blessing on Abijah were the cities he was able to take from Israel (v. 19), the death of his enemy Jeroboam (v. 20), his power (v. 21), and his many children (v. 21). Though marrying many wives was a sin, fathering many children was an evidence of divine blessing (fruitfulness).
