Charles H. Spurgeon on Psalms 119:70

Their heart is as fat as grease. The word vpj occurs nowhere else in Scripture, but with the Chaldees vpj signifies to fatten, to make fat; also to make stupid and doltish, because such the fat ofttimes are... For this reason the proud, who are mentioned in the preceding verse, are described by their fixed resolve in evil, because they are almost insensible; as is to be seen in pigs, who pricked through the skin with a bodkin, and that slowly, as long as the bodkin only touches the fat, do not feel the prick until it reaches to the flesh. Thus the proud, whose great prosperity is elsewhere likened to fatness, have a heart totally insusceptible, which is insensible to the severe reproofs of the Divine word, and also to its holy delights and pleasures, by reason of the affluence of carnal things; aye, more, is altogether unfitted for good impulses; just as elsewhere is to be seen with fat animals, how slow they are and unfit for work, when, on the contrary, those are agile and quick which are not hindered by this same fatness. Martin Geier.