Hazrat Imran bin Husain says that committing adultery with the sister-in-law will make the wife unlawful.

Hazrat Ibn Abbas (may Allah be pleased with them both) says that committing adultery with the sister-in-law does not make the wife unlawful.

Hazrat Abu Al-Wadain narrates that once a man married the daughter of a man from Syria, whose title was "Ibnat Muheerah" (she was called Muheerah because her dowry was high). But on the wedding night, he was presented with another daughter whose title was "Ibnat Fataah" (her dowry was less). When the man had intercourse with the girl that night, he asked, "Who are you?" She replied, "I am Ibnat Fataah." The man said, "Your father married me to Ibnat Muheerah." So they took their case to Hazrat Muawiyah bin Abi Sufyan (may Allah be pleased with him). Hazrat Muawiyah (may Allah be pleased with him) said, "A woman has been exchanged for a woman, so there is no dispute." Hazrat Muawiyah (may Allah be pleased with him) consulted the Syrian scholars present with him about this matter, and they also gave the same verdict. Then the man said, "I want to take this case to Hazrat Ali (may Allah be pleased with him)." Hazrat Muawiyah (may Allah be pleased with him) permitted him. The case was presented before Hazrat Ali (may Allah be pleased with him), so he picked up a trivial thing from the ground and said, "For me, deciding this case is even more trivial than this thing." The woman will receive as much dowry as you paid her to make her private parts lawful for you. And it is obligatory upon her father to give the other daughter the wealth that you paid, and you should not go near her until the first girl completes her waiting period ('iddah). The narrator says, "I think Hazrat Ali (may Allah be pleased with him) had the girl's father flogged or intended to have him flogged."

Hazrat Umar (may Allah be pleased with him) narrates that once the Prophet (peace be upon him) said in a sermon: "Arrange marriages for unmarried people." A man stood up and asked, "O Messenger of Allah! What will be their dowries?" The Prophet replied, "Whatever their families are pleased with."

The grandfather of Hazrat Ibn Abi Labeebah narrates that the Prophet (peace be upon him) said: "Whoever made a woman lawful (for marriage) even with one dirham, she became lawful for him." The verdict of Hazrat Waki’ was also the same, that giving one dirham as mahr is also permissible.

17155 - He said: And I heard Waki‘ (giving a fatwa) (1) about it, saying: He may marry her for one dirham.

Hazrat Amir bin Rabi’ah narrates that during the Prophetic era, a man married a woman in exchange for two shoes as mahr, and the Prophet (peace be upon him) declared this marriage valid.

Hazrat Sahl bin Sa’d (may Allah be pleased with him) narrates that the Noble Prophet (peace and blessings be upon him) married a man to a woman on the condition that he would teach her a surah from the Holy Qur’an as her dowry.

Hazrat Saeed bin Musayyib says that if a woman agrees to accept a whip (lash) as her dower, then that will become her dower.

Hazrat Anas bin Malik (may Allah be pleased with him) narrates that Hazrat Abdur Rahman bin Auf (may Allah be pleased with him) contracted marriage in exchange for a nugget of gold, and that nugget was equal to three dirhams and one third of a dirham.