“When the following was revealed: “And Hajj (pilgrimage to Makkah) to the House (Ka’bah) is a duty that mankind owes to Allah, for whoever can bear the way.” [3:97] They asked: ‘O Messenger of Allah, is Hajj every year?’ He remained silent. They asked: ‘Is it every year?’ He said: ‘No. If I had said yes, it would have become obligatory.’ Then the following was revealed: “O you who believe! Ask not about things which, if made plain to you, may cause you trouble.’” [5:101]  

لَمَّا نَزَلَتْ {وَلِلَّهِ عَلَى النَّاسِ حِجُّ الْبَيْتِ مَنِ اسْتَطَاعَ إِلَيْهِ سَبِيلاً} قَالُوا يَا رَسُولَ اللَّهِ الْحَجُّ فِي كُلِّ عَامٍ فَسَكَتَ ثُمَّ قَالُوا أَفِي كُلِّ عَامٍ فَقَالَ لاَ وَلَوْ قُلْتُ نَعَمْ لَوَجَبَتْ فَنَزَلَتْ {يَا أَيُّهَا الَّذِينَ آمَنُوا لاَ تَسْأَلُوا عَنْ أَشْيَاءَ إِنْ تُبْدَ لَكُمْ تَسُؤْكُمْ }  

“They said: ‘O Messenger of Allah, is Hajj (required) every year?’ He said: ‘If I were to say yes, it would have become obligatory, and if it were to become obligatory, you would not (be able to) do it, and if you did not do it you would be punished.’”  

قَالُوا يَا رَسُولَ اللَّهِ الْحَجُّ فِي كُلِّ عَامٍ قَالَ لَوْ قُلْتُ نَعَمْ لَوَجَبَتْ وَلَوْ وَجَبَتْ لَمْ تَقُومُوا بِهَا وَلَوْ لَمْ تَقُومُوا بِهَا عُذِّبْتُمْ  

“O Messenger of Allah, is Hajj (required) every year, or just once” He said: “Rather it is just once. And whoever can perform Hajj voluntarily, let him do so.”  

أَنَّ الأَقْرَعَ بْنَ حَابِسٍ سَأَلَ النَّبِيَّ ﷺ فَقَالَ يَا رَسُولَ اللَّهِ الْحَجُّ فِي كُلِّ سَنَةٍ أَوْ مَرَّةً وَاحِدَةً قَالَ بَلْ مَرَّةً وَاحِدَةً فَمَنِ اسْتَطَاعَ فَتَطَوُّعٌ