Standing next to the kid getting picked on is the loudest sermon you’ll ever preach.

Standing beside someone while they are being laughed at says more than any speech about what you believe. It reorders the room. The person doing the picking loses the audience, and the person on the receiving end learns they are not alone, which is where most of the damage was coming from. That is a sermon nobody had to sit through.

You do not have to confront anybody or put yourself in danger for this. Sit down next to them, walk out with them, say something ordinary about the homework. If the situation needs an adult, get one, and that is not snitching, it is help.