Abu Hurairah
The most authentic opinion according to "Saifur Rahman al Mubararakpuri", however, is that Dhat Ar-Riqa‘ campaign took place after the fall of Khaibar (and not as part of the Invasion of Nejd). This is supported by the fact that Abu Hurairah and Abu Musa Al-Ash‘ari witnessed the battle. Abu Hurairah embraced Islam only some days before Khaibar, and Abu Musa Al-Ash‘ari came back from Abyssinia (Ethiopia) and joined Muhammad at Khaibar. The rules relating to the prayer of fear which Muhammad observed at Dhat Ar-Riqa‘ campaign, were revealed at the Asfan Invasion and these scholars say, took place after Al-Khandaq (the Battle of the Trench).