The Trans-Jordanian Tribes (1 Chronicles 5) February 9-10
Chapter 5 concerns the tribes who settled east of the Jordan—Reuben, Gad and half of Manasseh.
Notice verses 1-2 in the New Revised Standard Version: "The sons of Reuben the firstborn of Israel. (He was the firstborn, but because he defiled his father's bed [when he slept with his father's concubine Bilhah] his birthright was given to the sons of Joseph son of Israel, so that he [Reuben] is not enrolled in the genealogy according to the birthright; though Judah became prominent among his brothers and a ruler ["the chief ruler," King James Version] came from him, yet the birthright belonged to Joseph)."
This passage is important in explaining two things. First, the transfer of the birthright from Jacob's firstborn son. And second, the fact that the birthright and kingship were split up. Reuben, though the firstborn of Jacob by his first wife Leah, was not permitted to receive the birthright blessing upon his descendants (or the promise of kingship) because of the defilement he brought on himself. Instead the two elements of birthright and scepter were split out and went to the next two in line. The kingship went to the fourth son of Jacob by Leah, Judah, skipping over Leah's second and third sons, Simeon and Levi, presumably because they were not entitled to tribal territory and dominion, having disqualified themselves through their cruelty (Genesis 49:5-7; 34:25-30). The birthright went to another firstborn, Joseph—Jacob's firstborn by his other wife Rachel (skipping over Jacob's children by his concubines Bilhah and Zilpah).
This chapter further informs us that in the days of Saul, the Reubenites and Gadites fought against the Hagrites (verses 10, 18-19), perhaps meaning descendants of Hagar (and thus Ishmaelite or related Arab tribes). "The Hagrites and their allies were probably desert peoples who felt increasing pressure from the expanding Israelite population. Their efforts at resisting the Israelites took place in the days of Saul (v. 10), though the narratives of Saul do not mention them" (Nelson Study Bible, note on verse 19). We see here in the midst of these genealogies another example of crying out for God's help and His answering prayer (verses 20-22)—though here God answers collective prayer rather than that of an individual, as in the previous chapter with Jabez.
Finally, we earlier read the end of chapter 5, regarding the trans-Jordanian tribes' deportation to Assyria, in harmony with Israel's history in the book of Kings (see Bible Reading Program comments on 2 Kings 16:6-9; 15:29-31; 1 Chronicles 5:23-26; 2 Kings 17:1-2; 16:10-18; 15:38; 2 Chronicles 27:9).