What is the interpretation of the Hadith, "When two Muslims meet with their swords, both the slayer and the slain will be in the Hellfire," in light of the Battle of the Camel, taking into consideration that the Companions were Mujtahids and were promised Paradise?

The meaning of the hadith (definition) is that blessings in this world do not last for their recipients; they are fleeting. A believer knows this and prepares for the Hereafter, so he does not rejoice in this world with a joy that makes him forget its ultimate destiny, nor does he grieve over its loss with a grief that harms him.