Narrated Abu Dharr:
that the Messenger of Allah (ﷺ) said: There is no one more truthful in speech, nor in fulfilling of promises, that sky has covered and the earth has carried, than Abu Dharr, the likeness of 'Eisa bin Mariam. So 'Umar bin Al-Khattab said, as if out of envy: So do you acknowledge that for him, O Messenger of Allah? He said: Yes, so acknowledge it.