Gunmen kill more than 160 people in attacks on two west Nigeria villages | Nigeria

Residents told Reuters the gunmen were jihadists who often preached in the village and that they demanded that locals ditch their allegiance to the Nigerian state and switch to sharia law. When the villagers pushed back, the militants opened fire during Tuesday’s sermon, they said.

The motive almost certainly is power - gaining and maintaining it.

I think it’s a sign of good character to not be able to fathom doing this. Unfortunately however, we have to keep in mind that humans can be manipulated to anything, given the according circumstances.