John Gill Commentary 2 Samuel 20

And there happened to be a man of Belial
A wicked man, as the Targum, a lawless, yokeless man, that had cast off the yoke of the law, and was without it, as Belial is by some interpreted; or one unprofitable and useless, yea, noxious and pernicious: this man, though, with respect to second causes, may be said to be there by chance, yet it was so ordered by the providence of God that he should be present at this time for the further fulfilment of the threatening to David, that the sword should not depart from his house.

whose name [was] Sheba, the son of Bichri, a Benjamite ;
one perhaps that had been in the rebellion of Absalom, and had a grudge against David for the removal of the kingdom out of that tribe:

and he blew a trumpet ;
which was done to draw off the Israelites from David, and gather a party to himself:

and said, we have no part in David ;
so he interpreted what the men of Judah said, because they claimed kindred to David, the rest of the Israelites had no interest in him; thus they, who just before said they had ten parts in him, now had none at all:

neither have we inheritance in the son of Jesse ;
so he calls David by way of contempt, as if he was no king, but a private person, and a descendant from a mean family:

every man to his tent, O Israel ;
there to consider what to do, and whom to choose to be their king, and let Judah take David for their king, and enjoy him alone, since they had so slighted, and dealt so injuriously and roughly with the rest of the tribes.

So every man of Israel went up from after David
Those that met him on the road departed from him, and went no further with him:

[and] followed Sheba the son of Bichri ;
and made him their captain, who was the author of their mutiny and sedition:

but the men of Judah clave unto their king, from Jordan to Jerusalem :
never left him, after they had conducted him over Jordan, until they had brought him safely to Jerusalem.

And David came to his house at Jerusalem
His palace there, which was in that part of the city called the fort of Zion, and city of David:

and the king took the ten women [his] concubines, whom he had left to
keep the house ;
when he fled from Jerusalem because of Absalom, (2 Samuel 15:16) ;

and put them in ward ;
partly as a punishment for easily yielding to the lust of Absalom, and partly that they might not be seen, which would bring to remembrance his sin:

and fed them ;
he did not put them to death, nor put them away, but kept them thus confined, and made a proper provision for them, not suffering them to marry any other, and be maintained by them:

but went not in unto them :
into their apartments to lie with them, having been defiled by his son, (2 Samuel 16:22) ;

so they were shut up unto the day of their death ;
kept in the ward till they died:

living in widowhood ;
neither used by the king as his concubines, as they had been before, nor suffered to marry any other; or "in the widowhood of life" ^F15 , which is so expressed, to distinguish it from widowhood made by death; this was such sort of widowhood as obtained while their husband was living;

so the Targum, ``widows of their husband alive,'' or remaining.

FOOTNOTES:

• F15: (twyx twnmla) "in viduitate vitae", Pagninus, Montanus.

Then said the king to Amasa
Whom he had promised to make general of his army, (2 Samuel 19:13) ; and by the following order declared him such:

assemble me the men of Judah within three days ;
which was done by the sound of the trumpet, or by the proclamation of a herald; it seems that the men of Judah, who attended David to Jerusalem, were gone to their respective cities and places of abode, or there would have been no occasion for such a summons; though it is strange they should, when the men of Israel appeared so inclinable to a new rebellion:

and be thou here present ;
to take the command of them.

So Amasa went to assemble [the men of] Judah
To gather, them together out of their several tribes, and bring them to Jerusalem:

but he tarried longer than the set time which he had appointed him :
than the three days; whether this was owing to the remissness of Amasa, or the unwillingness of the people to serve under him, who had been Absalom's general in the late rebellion, or not having time sufficient allowed him, is not certain.