Hadith: Ibn ‘Abbās (may Allah be pleased with him) said: If [a man] forbids his wife, this is nothing. He further quoted: {There is in the Messenger of Allah a good example to you} [Sūrat al-Ahzāb: 21]

عن ابن عباس رضي الله عنهما أنه كان يقول: «إذا حَرَّمَ امرأته ليس بشيء» وقال: {لقد كان لكم في رسول الله أُسْوَةٌ حَسَنَةٌ} [الأحزاب: 21]
[صحيح] - [رواه البخاري]

Ibn ‘Abbās (may Allah be pleased with him) said: "If [a man] forbids his wife, this is nothing." He further quoted: {There is in the Messenger of Allah a good example to you.} [Sūrat al-Ahzāb: 21]
[Authentic hadith] - [Narrated by Bukhari]

Explanation

This report means that if a man says to his wife: "You are unlawful for me," or: "You are forbidden," or something similar, this saying does not constitute divorce. It will be treated like a normal oath for which an expiation is required. In this respect, Allah, the Almighty, says: {O Prophet, why do you prohibit [yourself from] what Allah has made lawful for you, seeking the approval of your wives? And Allah is Forgiving and Merciful. Allah has already ordained for you [Muslims] the dissolution of your oaths. And Allah is your protector, and He is the Knowing, the Wise} [Sūrat At-Tahrīm: 1-2]. The last verse means that Allah ordained for the Muslims the dissolution of their oath by making the expiation that is stipulated in Sūrat al-Mā’idah.