Deuteronomy 23:15-16 KJV
(15) Thou shalt not deliver unto his master the servant which is escaped from his master unto thee:
(16) He shall dwell with thee, even among you, in that place which he shall choose in one of thy gates, where it liketh him best: thou shalt not oppress him.
According to the customs of the time, it is clear in the Bible that people were buying other people to work.
THE BOUGHT SERVANT WAS TO BE AS HEBREW AS THE HOMEBORN HEBREW NOT A SLAVE OR AN OPPRESSED
The foreigner that was bought for money for his service in Israel was seen by Jesus as an integral part of His people or of the family who bought him, not like a hired servant or like a lower-class citizen. Because he was to be circumcised like the Hebrew and permitted to eat the Passover and even the holy things which only priests and his immediate family may eat, something that was forbidden for a hired servant and for a fellow Hebrew (Leviticus 22:10-13).
Exodus 12:43-45 KJV
(43) And the LORD said unto Moses and Aaron, This is the ordinance of the passover: There shall no stranger eat thereof:
(44) But every man's servant that is bought for money, when thou hast circumcised him, then shall he eat thereof.
(45) A foreigner and an hired servant shall not eat thereof.
Leviticus 22:10-13 KJV
(10) There shall no stranger eat of the holy thing: a sojourner of the priest, or an hired servant, shall not eat of the holy thing.
(11) But if the priest buy any soul with his money, he shall eat of it, and he that is born in his house: they shall eat of his meat.
(12) If the priest's daughter also be married unto a stranger, she may not eat of an offering of the holy things.
(13) But if the priest's daughter be a widow, or divorced, and have no child, and is returned unto her father's house, as in her youth, she shall eat of her father's meat: but there shall no stranger eat thereof.
Then, again, how the Hebrews apply Moses was a different story. God cannot be blamed for how the world treated their workers as oppressed things when He decrees how a servant must be treated in Israel. What matters is how Jesus intends His will, which is the will of God the Father, to be strictly followed.
Note that even though Jesus forbids the displeasing behaviors He did not eradicate those who chose those behaviors.
Deuteronomy 4:2 KJV
(2) Ye shall not add unto the word which I command you, neither shall ye diminish ought from it, that ye may keep the commandments of the LORD your God which I command you.
Deuteronomy 5:32 KJV
(32) Ye shall observe to do therefore as the LORD your God hath commanded you: ye shall not turn aside to the right hand or to the left.