It was
narrated that ‘Ali said:
“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]