Jamieson, Fausset and Brown on 1 Chronicles 12:39-40

39-40. there they were with David three days, eating and drinking--According to the statements made in the preceding verses, the number of armed warriors assembled in Hebron on this occasion amounted to three hundred thousand. Supplies of provisions were abundantly furnished, not only by the people of the neighborhood, but from distant parts of the country, for all wished the festivities to be on a scale of liberality and magnificence suitable to the auspicious occasion.