Joking with words that involve disbelief (kufr) or immorality (fisq) is something that exists in some Muslim societies. We hope your Eminence can shed light on this matter and clarify the position of students of knowledge and preachers regarding it.
Answer:
There is no doubt that joking with lies or with words that contain forms of disbelief is among the gravest of evils and one of the most dangerous matters that can occur among people in their gatherings. It is obligatory to beware of this.
Allah has warned against it in His saying:
وَلَئِنْ سَأَلْتَهُمْ لَيَقُولُنَّ إِنَّمَا كُنَّا نَخُوضُ وَنَلْعَبُ قُلْ أَبِاللَّهِ وَآيَاتِهِ وَرَسُولِهِ كُنْتُمْ تَسْتَهْزِئُونَ لا تَعْتَذِرُوا قَدْ كَفَرْتُمْ بَعْدَ إِيمَانِكُمْ
“And if you ask them, they will surely say, ‘We were only conversing and playing.’ Say, ‘Is it Allah and His verses and His Messenger that you were mocking?’
Make no excuse; you have disbelieved after your belief.”
(Surah At-Tawbah, 9:65–66)
Many of the Salaf (pious predecessors), may Allah have mercy on them, said that this verse was revealed concerning a group of people who said among themselves during one of the journeys with the Prophet ﷺ:
“We have never seen people like these reciters of ours — more greedy in their stomachs, more lying in their speech, and more cowardly in battle.”
So Allah revealed this verse about them.
It is authentically reported from the Prophet ﷺ that he said:
«وَيْلٌ لِلَّذِي يُحَدِّثُ فَيَكْذِبُ لِيُضْحِكَ بِهِ الْقَوْمَ، وَيْلٌ لَهُ، ثُمَّ وَيْلٌ لَهُ»
“Woe to the one who speaks and lies in order to make people laugh. Woe to him, then woe to him.”
(Narrated by Abu Dawood, al-Tirmidhi, and al-Nasa’i with a sound chain of narration)
Therefore, it is incumbent upon the people of knowledge and all believing men and women to beware of this and to warn others against it, because of the great danger, serious corruption, and severe consequences it entails.
May Allah protect us and the Muslims from this, and guide us all to His straight path. Indeed, He is the All-Hearing, the Responsive.
Reference:
Majmūʿ Fatāwā wa Maqālāt of Shaykh ʿAbd al-ʿAzīz ibn Bāz, vol. 7, p. 45.