I was sitting next to Zayd bin Arqam when someone asked him, "How many military expeditions did the Prophet ﷺ undertake?"He replied, "Nineteen."The person asked, "How many did you take part in with him?"He answered, "Seventeen."I asked, "Which was the first of them?"He said, "Al-Usayrah, or al-Ushayr."
كنت إلى جنب زيد بن أرقم، فقيل له: كم غزا النبي ﷺ من غزوة؟ قال: تسع عشرة. قيل: كم غزوت أنت معه؟ قال: سبع عشرة. قلت: فأيهم كانت أول؟ قال: العسيرة أو العشير.
Bukhari related it in the Book of Maghazi (3949), and Muslim in the Book of Jihad (1254:143), both through the route of Shubah, from Abu Ishaq, who mentioned it.His statement, "Useerah," with a seen, though it is also said with a sheen, "Usheerah." It is a place near Yanbu, inhabited by Banu Mudlij, and this place has now disappeared, situated near Ayn al-Barakah, which is still known today.His statement, "Which was the first? He said, Usheerah..." This is what Zayd bin Arqam said, while others said that before the raid of Usheerah there were two raids, one being the raid of Wadan, also called the raid of Abwa, and the second the raid of Buwat, as will come later. Zayd bin Arqam's statement here limits the raids of the Prophet ﷺ to nineteen. Jabir mentioned that he took part with the Messenger of Allah ﷺ in nineteen raids, and he did not witness Badr or Uhud, which brings the number of the Prophet's ﷺ raids to twenty-one. His statement thus negates this restriction, and this is the correct view. It is established among the scholars of the biography that the Prophet's ﷺ raids were more than nineteen. So Zayd bin Arqam's statement is to be understood as based on his own knowledge, or as reflecting a difference of opinion regarding the number of raids.