Psalms 38:7

For my loins are filled with a loathsome [disease]: and [there is] no soundness in my flesh.

Ver. 7. For my loins are filled with a loathsome disease] The loins, those scats of lust, are now grievously inflamed and pained with some imposthumated matter or pestilential carbuncle: Morbo vilissimo quem nominare dedecet, saith Aben Ezra. Femora mea prorsus occupat ardens uleus (Vat.). In quibus est concupiscentia (Theodoret). God oft punisheth sin in kind, and speaketh to the conscience in its own language, that such a sickness was the fruit of such a sin.

And there is no soundness in my flesh]

Principium dulce est, sed finis Amoris amarus,

Laeta venire Venus, tristis abire solet.

Sin is as the poison of asps, which first tickles him that is stung, and maketh him laugh; till, by little and little, it gets to the heart and then puts him to intolerable torture.