Interior Bench I is built in the Church for 2 Wooden Plank and 6 Bronze Nails. +3 church quality. Unlocked by Church Cleaning. Its construction site needs Building mastery 2: below that, hits do nothing.
It adds 3 to church quality. More elaborate sermons need a higher church quality. Each new best church quality counts towards the Sacred Interior inspiration. Church Cleaning also unlocks Improve the Church I.