

If the seller refuses to do any of the above, walk away from the sale.

Again, if this was done, you'll see the "Set up your iPhone" screen. He'll also need to go to Settings > General > Reset > Erase All Content and Settings to erase the device. Ask the seller to log in with his Apple ID and password to activate the device. If the device asks for an Apple ID and password, it's locked and worthless to you in its current state.

After this is done, the "Set up your iPhone" screen should appear. Ask the seller to go to Settings > General > Reset > Erase All Content and Settings and erase the device.
