Al-Baqara 2:229

Divorce may be pronounced twice; then either retaining in all kindness, or separating in the best way. It is not lawful for you to take back anything that you have given them [of dowry], except when they both fear that they would not be able to maintain the limits ordained by Allah. So if you fear that they would not be able to maintain the limits set by Allah, then there is no sin upon either of them if she opts to give something for her release[121]. These are the limits ordained by Allah, so do not exceed them; whosoever exceeds the limits ordained by Allah, it is they who are the wrongdoers.

[121] Al-Khul‘ means the parting of a wife from her husband by returning the sum of money she received from him as dowry or gifts in exchange for conceding to her demand for divorce.

Divorce is twice. Then [after that], either keep [her] in an acceptable manner or release [her] with good treatment. And it is not lawful for you to take anything of what you have given them unless both fear that they will not be able to keep [within] the limits of Allāh.[89] But if you fear that they will not keep [within] the limits of Allāh, then there is no blame upon either of them concerning that by which she ransoms herself. These are the limits of Allāh, so do not transgress them. And whoever transgresses the limits of Allāh - it is those who are the wrongdoers [i.e., the unjust].

[89] i.e., deal fairly with each other.

229. The divorce is twice, after that, either you retain her on reasonable terms or release her with kindness. And it is not lawful for you (men) to take back (from your wives) any of your Mahr (bridal-money given by the husband to his wife at the time of marriage) which you have given them, except when both parties fear that they would be unable to keep the limits ordained by Allâh (e.g. to deal with each other on a fair basis). Then if you fear that they would not be able to keep the limits ordained by Allâh, then there is no sin on either of them if she gives back (the Mahr or a part of it) for her Al-Khul‘ (divorce)[60]. These are the limits ordained by Allâh, so do not transgress them. And whoever transgresses the limits ordained by Allâh, then such are the Zâlimûn (wrong-doers).

[60] (V.2:229) Al-Khul‘ * الخلع and how a divorce is given according to it.
Narrated Ibn ‘Abbâs رضي الله عنهما: The wife of Thâbit bin Qais came to the Prophet صلى الله عليه وسلم and said, "O Allâh’s Messenger! I do not blame Thâbit for defects in his character or his religion, but I, being a Muslim, dislike to behave in an un-Islâmic manner (if I remain with him)". On that Allâh’s Messenger صلى الله عليه وسلم said (to her), "Will you give back the garden which your husband has given you as Mahr )?" She said, "Yes." Then the Prophet صلى الله عليه وسلم said to Thâbit, "O Thabît! Accept your garden, and divorce her once." (Sahih Al-Bukhâri, Vol.7, Hadîth No. 197).
* Al-Khul‘ الخلع means the parting of a wife from her husband by giving him a certain compensation.

Divorce must be pronounced twice and then (a woman) must be retained in honour or released in kindness. And it is not lawful for you that ye take from women aught of that which ye have given them; except (in the case) when both fear that they may not be able to keep within the limits (imposed by) Allah. And if ye fear that they may not be able to keep the limits of Allah, in that case it is no sin for either of them if the woman ransom herself. These are the limits (imposed by) Allah. Transgress them not. For whoso transgresseth Allah's limits: such are wrong-doers.