John Gill Commentary 1 Kings 14:18

"And all Israel buried him, and mourned for him, according to the word of Jehovah, which he spake by his servant Ahijah the prophet." — 1 Kings 14:18 (ASV)

And they buried him
In an honourable manner, suitable to his rank and pedigree:

and all Israel mourned for him, according to the word of the Lord,
which he spoke by the hand of his servant Ahijah the prophet ,
(1 Kings 14:13) .