Albert Barnes Commentary 2 Samuel 21

There is no note of time whatever, nor any clue as to what part of David’s reign the events of this chapter ought to be assigned.

Enquired of the Lord - The Hebrew is “sought the face of the Lord,” a phrase quite different from that so often used in Judges (for example, Judges 1:1) and the Books of Samuel. This probably indicates that this chapter is from a different source. This inference agrees with the indefinite phrase “in the days of David” and with the allusion to the slaughter of the Gibeonites, which has not been narrated elsewhere.

And for his bloody house - This literally means “the house of blood,” that is, the house or family upon which rests the guilt of shedding innocent blood.

The way the writer here refers to the history of the league with the Gibeonites (Joshua 9) shows that the Book of Joshua was not part of the same work as the Books of Samuel.

Of the Amorites—The Gibeonites were Hivites (Joshua 9:7; Joshua 11:19), and in many enumerations of the Canaanite nations, the Hivites are distinguished from the Amorites. But “Amorite” is often used in a more comprehensive sense, equivalent to “Canaanite” (Deuteronomy 1:27), and denotes especially that part of the Canaanite nation which lived in the hill country (Numbers 13:29; Deuteronomy 1:7, 20, 24), and so includes the Hivites.

No silver, nor gold... - Money payments as compensation for blood-guilt were very common among many nations. The law, too, in Numbers 35:31-32, presupposes the existence of the custom which it prohibits. In like manner, the speech of the Gibeonites implies that such a payment as they refuse would be a not unusual proceeding.

Neither... shall you kill any man in Israel - They mean that it is not against the nation of Israel, but against the individual Saul, that they cry for vengeance. The demand for Saul’s sons is exactly similar to that which dictated David’s own expression in 2 Samuel 24:17: against me, and against my father’s house.

Seven men - Seven was a sacred number not only with the Hebrews but with other Eastern nations (Numbers 23:1, 29), and is therefore used on this occasion when the judicial death of Saul's sons was a religious act intended to appease God's wrath for the violation of an oath (Numbers 25:4).

Whom the Lord did choose - Rather, “the Lord’s chosen,” or elect. The same phrase is applied to Moses (Psalms 106:23), to the Israelites (Isaiah 43:20), and to Christ (Isaiah 42:1).

The Lord’s oath - The calamity brought upon Israel by Saul’s breach of the oath to the Gibeonites would make David doubly careful in the matter of his own oath to Jonathan.