Why did the Prophet (peace be upon him) command his Companions to exit the state of ihram during the Farewell Pilgrimage, for those who had not brought sacrificial animals, even though a solitary pilgrim performing Hajj is not obligated to offer a sacrifice?

Driving the sacrificial animal (hady) is not obligatory for any ritual; rather, it is a recommended supererogatory act for anyone who intends to visit Mecca for Hajj or 'Umrah, and it is also recommended for those who remain in their homelands. It is obligatory for the one who drives the hady not to exit his state of ihram until the hady reaches its designated place, meaning the Day of Sacrifice or until it is slaughtered. The Prophetic hadith indicates that for one who drives the hady, it is preferable to perform Hajj al-Qiran, and for one who does not, it is preferable to perform Hajj al-Tamattu'.