From page 48-49 of section 1…

…the saints have ever had their armour, and the preaching of the gospel unlocks it. As gospel-light ascends, so Satan’s shady kingdom of darkness vanisheth…he labours either by persecution to drive the gospel away, or by policy to persuade a people to send it away from their coasts.

from section 1, page 21…

“God brings his grace into the heart by conquest. Now, as in a conquered city, though some yield and become true subjects to the conqueror, yet others plot how they may shake off this yoke; and therefore it requires the same power to keep, as was to win it at first.”