Charles H. Spurgeon on Psalms 38:7

For my loins are filled with a loathsome disease. The word here used, according to Gesenius (Lex.), properly denotes the internal muscles of the loins near the kidneys, to which the fat adheres. The word rendered loathsome —the word disease being supplied by our translators —is derived from (hlq), kalah, a word which means to roast, to parch, as fruit, grain, etc.; and then, in the form used here, it means scorched, burned; hence, a burning or inflammation; and the whole phrase would be synonymous with an inflammation of the kidneys. The word here used does not imply that there was any eruption, or ulcer, though it would seem from verse five that this was the fact, and that the inflammation had produced this effect. Albert Barnes.