It was called after the location it took place between Mecca and Medinah
It happened in the month of Jumada Al-Akhira In the second year of Hijra, in Yanba valley between Mecca and Medinah.
The Messenger (peace be upon him) led the army and his uncle Hamzah ibn Abdul-Muttalib (may Allah be pleased with him) was the flag-bearer
The army was sent out to catch Quraish’s caravan which had attacked the Muslims. This was a necessary step the Messenger (peace be upon him) and his Companions took to establish the new Islamic nation and Allah’s call, after patiently withstanding many years of harm from the disbelievers. The expedition happened with the permission of Allah, aiming to stop the attacks of the disbelievers.
The Messenger (peace be upon him) left with about 150 Muhajareen (Immigrants from Mecca) and about 30 horses and camels to intercept a caravan belonging to Quraish and travelling to Ash-Sham.
The Messenger (peace be upon him) had ordered Abu Salamah ibn Abdul-Asid Al-Makhzoomy to dispose of affairs in Medianah in his (peace be upon him) absence. Abu Salamah was a brother of the Messenger (peace be upon him) through breastfeeding, and the son of his aunt on his father’s side called Barrah, and one of the first people to enter Islam. The Messenger (peace be upon him) had received news that the caravan had left Mecca with money. However, the caravan had passed by Thil Ushairah a few days before the Muslims reached this location. The same caravan was the reason for the following major battle of Badr, when it returned from Ash-Sham.
The Messenger (peace be upon him) wrote treaties (after this expedition) with Banu Madlij and their allies Bani Dhumrah that they would not attack the Muslims.
In this battle, the Messenger (peace be upon him) jokingly gave Ali ibn Abu Talib the nickname ‘Father of the Dust’, when he found him and Ammar Ibn Yasir asleep and dust had covered him. The Messenger (peace be upon him) woke him up by nudging him with his leg, and said to him, <Get up, Father of the Dust,> due to the dust he saw on him.
There was no fighting during this expedition, but a treaty was written with Banu Madlij.
Through these expeditions and campaigns, the Messenger (peace be upon him) was able to strengthen the Islamic call. This strength resulted in hatred and fear in the hearts of the disbelievers. This is because the Muslims’ strength threatened the disbelievers’ power and their status. We also learn that the Messenger (peace be upon him) also benefitted politically from these expeditions by gaining the support of the different tribes on the route between Mecca and Medinah. From this tactic, the Messenger’s wisdom as a leader became clear.
At-Tabaqat by Ibn Saad (2/10). The Prophet’s Biography written in Al-Hallab, the chapter on the Thil Ushairah expedition. The Prophet’s Biography by Ibn Hesham (2/601).