'Rigor' in the Bible

Thou shalt not rule over him with rigor, but shalt fear thy God.

And ye shall make them an inheritance for your children after you, to hold for a possession; of them shall ye take your bondmen for ever: but over your brethren the children of Israel ye shall not rule, one over another, with rigor.

As a servant hired year by year shall he be with him: he shall not rule with rigor over him in thy sight.