الكافي- ط الاسلامية, volume 5, page 414

1. A number of our people have narrated from Sahl ibn Ziyad and Ali ibn Ibrahim has narrated from his father all from Ahmad ibn Muhammad from ibn abu Nasr who has said the following: “I once asked abu al-Hassan (a.s.), about the meaning of the words of Shu‘ayb, ‘(Shu‘ayb) said to (Moses), “I want to give one of my daughters to you in marriage on the condition that you will work for me for eight years, but you may continue for two more years only out of your own accord’” (28:27) and that which one of the terms he completed. He (the Imam) said, ‘Completion was of the longest term which was ten years.’ I then asked, ‘Did he go to bed before completing the term or afterwards?’ He (the Imam) said, ‘It was before completing the terms.’ I then asked, ‘If a man marries a woman and stipulates with her father for the wages of two months if it is permissible.’ He (the Imam) said, ‘Moses knew that he will complete the terms. How can this man know that he remains alive until the time of paying? At the time of the Messenger of Allah, O Allah, grant compensation to Muhammad and his family worthy of their services to Your cause, people married women for teaching a chapter of al-Quran, for one dirham and for one handful of wheat.’”

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.

2. Ali ibn Ibrahim has narrated from his father from al-Nawfaliy from al-Sakuniy who has said the following: “Abu ‘Abd Allah (a.s.), has said, ‘Marriage is not lawful in Islam for hiring and saying, ‘I will work for you up to so and so many years and you give to me in marriage your daughter or sister.’ He (the Imam) said, ‘It is unlawful because it is the price of her neck and in fact she is the rightful person for her mahr (dower).”’

Translation: Muhammad Sarwar·Thaqalayn link·The Arabic above is the original.