But it does have some passages that seem to approve of it. For example:
It's OK to have sex with "women children" that are obtained in war.
And the LORD spake unto Moses, saying, Avenge the children of Israel of the Midianites ... And they warred against the Midianites, as the LORD commanded Moses; and they slew all the males ... And the children of Israel took all the women of Midian captives, and their little ones ... And Moses was wroth with the officers ... And Moses said unto them, Have ye saved all the women alive? ... Now therefore kill every male among the little ones, and kill every woman that hath known man by lying with him. But all the women children, that have not known a man by lying with him, keep alive for yourselves. Numbers 31:1-18
When thou comest nigh unto a city to fight against it ... And when the LORD thy God hath delivered it into thine hands, thou shalt smite every male thereof with the edge of the sword: But the women, and the little ones, and the cattle, and all that is in the city, even all the spoil thereof, shalt thou take unto thyself. Deuteronomy 20:10-14
How shall we do for wives for them that remain, seeing we have sworn by the LORD that we will not give them of our daughters to wives? ... And the congregation sent thither twelve thousand men of the valiantest, and commanded them, saying, Go and smite the inhabitants of Jabeshgilead with the edge of the sword, with the women and the children. And this is the thing that ye shall do, Ye shall utterly destroy every male, and every woman that hath lain by man. And they found among the inhabitants of Jabeshgilead four hundred young virgins, that had known no man by lying with any male: and they brought them unto the camp to Shiloh. Judges 21:7-11
Go and lie in wait in the vineyards; And see, and, behold, if the daughters of Shiloh come out to dance in dances, then come ye out of the vineyards, and catch you every man his wife of the daughters of Shiloh ... And the children of Benjamin did so, and took them wives, according to their number, of them that danced, whom they caught. Judges 21:20-23
It's OK to sell your daughter (no mention is made of age) to a man for him to use as a sex slave.
if a man sell his daughter to be a maidservant ... If she please not her master, who hath betrothed her to himself, then shall he let her be redeemed ... If he take him another wife; her food, her raiment, and her duty of marriage, shall he not diminish. Exodus 21:7-10