John Gill Commentary Jeremiah 48:29

"We have heard of the pride of Moab, [that] he is very proud; his loftiness, and his pride, and his arrogancy, and the haughtiness of his heart." — Jeremiah 48:29 (ASV)

We have heard the pride of Moab
Israel, and all the nations round about, had heard of this, and seen or heard of many instances of it; the thing was notorious; according to Kimchi, it is the prophet that here speaks in the name of the nations; but it seems best to understand it of the Lord himself, as appears from the (Jeremiah 48:30); and who here speaks in the plural number, because of the plurality of persons in the Godhead; as he afterwards does in the singular number, to denote the unity of the divine essence: (he is exceeding proud) his loftiness, and his arrogancy, and his
pride, and the haughtiness of his heart ;
a heap of words to express the same thing; suggesting that the instances of his pride were many, and that it was exceeding great indeed: these many words were little enough; and indeed words were wanting fully to declare it. The same was observed in Isaiah's time, and in much the same language; only more words are here used, to show that his pride was increased since that time; see (Isaiah 16:6).