John Gill Commentary 1 Kings 1:27

"Is this thing done by my lord the king, and thou hast not showed unto thy servants who should sit on the throne of my lord the king after him?" — 1 Kings 1:27 (ASV)

Is this thing done by my lord the king
With his knowledge and consent, and by his orders:

and you have not showed [it] unto your servant ;
meaning himself, who had brought him a message from the Lord, signifying that Solomon should succeed him; and therefore if that had been countermanded, it seemed strange that he should not have acquainted him with it: or "to your servants", as the Arabic version; for the word has a plural ending, though pointed as singular; and so it may mean not only himself, but the rest of David's faithful servants that were about him at court, as Kimchi observes:

who should sit on the throne of my lord the king after him ?
if he had altered his mind, or had had any direction from the Lord to make any change, he wondered that he had not acquainted him or any of his trusty friends with it.