Exodus 21:25

Now these are the judgments which thou shalt set before

If thou buy an Hebrew servant, six years he shall serve: and in the seventh he shall go out free for nothing.

If he came in by himself, he shall go out by himself: if he were married, then his wife shall go out

If his master have given him a wife, and she have born him sons or daughters; the wife and her children shall be her master's, and he shall go out by himself.

And if the servant shall plainly say, I love my master, my wife, and my children; I will not go out free: