(9:122) For there should separate from every division of them a group [remaining] to obtain understanding in the religion and warn their people when they return to them that they might be cautious.

 Imam Ridha(as) said: ,,Allah only ordered the Hajj so that they would all come as a group and seek their increase, and exit from all their errors committed by the servants.’Untill the Imam said:And let them be those who ponder and TRANSMIT AHADITH of the Imams(as) to every corner of the world, as Allah(swt) said:(9:122) For there should separate from every division of them a group [remaining] to obtain understanding in the religion and warn their people when they return to them that they might be cautious. 

And:(22:28)That they may witness benefits for themselves 

📚Wasail-ush-Shia V27,P96-97