24:33 And let them restrain themselves who cannot find a match, until Allah enriches them out of His grace. And among those whom your right hands possess who ask for a writing, then give them a writing if you know any good in them, and give them out of the wealth of Allah which He has given you. And do not force your slave-girls to an unchaste life,— when they desire to keep chaste,— in order to gain the goods of the life of this world. And whoever forces them, then Allah is, after their having been forced, most Forgiving, most Rewarding.
24:33 Those who cannot find a match should restrain their passion until they could be engaged in marriage. The message reiterates the ruling given in v. 2 and clearly prohibits premarital sex. By implication, those who have attained marriageable age, yet, due to pressure of, say, study, unemployment or other constrains, cannot engage in marriage, they must restrain their sexual urges ( cf. 23:5). In order to facilitate slaves to redeem their freedom, the master is required to give them assurance in writing, implied by the word kitāb (lit. book, writing), that they would be freed after paying redemption money to the master. The verse further requires the master to pay the redemption money to his slave in the form of charity or zakat to enable him or her 'earn' redemption money. The only condition being the master must ascertain the salve would be able to earn and maintain livelihood in an honest way upon setting free, implied by the clause if you know any good in them. Continuing with the rulings on slaves, the verse prohibits forcing women, particularly slave girls, and, by implication, other women caught in financial or societal constrains, into prostitution.