What is the authenticity of the hadith that mentions that the Prophet (peace be upon him) was on a journey, and Abu Bakr and Umar were with him, so they asked him for meat, and he said: "Have you not been satiated with meat by being shaded?" They said: "From where? By Allah, we have not had meat for days." He said: "From the meat of your companion whom you mentioned!" They said: "O Prophet of Allah, by Allah, we only said that he is weak, he is of no help to us in anything!" He said: "Did you say that?" Then the man returned to them and told them what he had said, so Abu Bakr and Umar came, and each of them said: "O Prophet of Allah, step on my earlobe and seek forgiveness for me," and he did so?