Charles H. Spurgeon on Psalms 17:10

"They are inclosed in their own fat," or their fat has inclosed them; either their eyes, that they can hardly see out of them, or their hearts, so that they are stupid and senseless, and devoid of the fear of God; the phrase is expressive of the multitude of their wealth, and increase of power, by which they were swelled with pride and vanity, and neither feared God nor regarded man; so the Targum paraphrases it, "their riches are multiplied, their fat covers them." —John Gill.