Thomas Shepard preaches on the consequences of spiritual drunkenness as described in Jeremiah 13:12-15, where God fills the inhabitants of the land with a spirit of drunkenness, leading to destruction and no mercy. The causes of this spiritual drunkenness include indulgence in sinful pleasures and corrupt counsel, resulting in staggering, blindness, rage, deep sleep, exposing of one's nakedness, and vomiting up corruption. This spirit of drunkenness is a forerunner of destruction when God fills people with delusions and they reject the truth, leading to division and misery. The preacher warns against spiritual drunkenness and urges to love the truth, seek counsel, and avoid deception.