In this verse Nathan set forth the evidence that led him to ask the question of the king. Essentially, he told the same story as Bathsheba but with additional detail. Not only did Nathan supply the guest list of the feast, but he added the information that the guests were in full agreement with Adonijah. They accepted his food and drink, but, most important of all, they acclaimed Adonijah king, saying, Long live King Adonijah!
These words are exactly parallel to the phrase used for the British monarch today, God save the King.
This last bit of information made it very certain that Adonijah looked—not to the future when he would be king—but to the present when he was king. It was, using a French phrase, a fait accompli (a circumstance already accomplished). If David did not put a stop to it as soon as possible, it would certainly succeed.
25 For he has gone down this day and has sacrificed oxen, fattened cattle, and sheep in abundance, and has invited all the king’s sons, the commanders of the army, and Abiathar the priest. And behold, they are eating and drinking before him, and saying, ‘Long live King Adonijah!’