How do I answer this interview question? Not sure if this is hurting my chances of getting a job?

One of my past employers was pushing me to do illegal and unethical things. I was also facing verbal abuse - yelling, lies spread about me etc. This was the only job where I had faced this. Most people were either unhappy or later realized what I had been put through. Anyway, I quit my job without having another job and was unemployed for a few months. It's been a few years now, but I'm unemployed again. What do I say at interviews why I left that position? Please advise.