Albert Barnes Commentary Nehemiah 9:25

"And they took fortified cities, and a fat land, and possessed houses full of all good things, cisterns hewn out, vineyards, and oliveyards, and fruit-trees in abundance: so they did eat, and were filled, and became fat, and delighted themselves in thy great goodness." — Nehemiah 9:25 (ASV)

Became fat. — that is, “grew proud,” or “wanton” — a phrase only occurring here, in the margin reference, and in (Jeremiah 5:28).

Delighted themselves — Rather, “luxuriated.” The word in the original does not occur elsewhere; but cognate terms make the sense clear.