John Gill Commentary Leviticus 25:43

"Thou shalt not rule over him with rigor, but shalt fear thy God." — Leviticus 25:43 (ASV)

You shall not rule over him with rigour As the Egyptians ruled over the Israelites, and made them to serve, (Exodus 1:13); where the same word is used as here, and seems designed to put them in mind of it, that so they might abstain from such usage of their brethren, which they had met with from their most cruel enemies; it signifies tyranny and oppression, treating them with great severity, laying hard and heavy tasks and burdens upon them they could not bear; enjoining them things they could not perform, and ordering them to do what were unnecessary, and without any limitation with respect to time:

but shall fear your God that has been good to you, and has brought you out of hard and rigorous bondage in Egypt; and which should be remembered with thankfulness, and they should fear to offend so good a God by using a brother cruelly.