question #2 Sahih al-Bukhari 3949, Book 64, Hadith 1 : What is the significance of Zaid bin Al-Arqam’s participation in the Prophet’s military expeditions?

Once, while I was sitting beside Zaid bin Al-Arqam, he was asked, “How many Ghazwat did the
Prophet undertake?” Zaid replied, “Nineteen.” They said, “In how many Ghazwat did you join him?”
He replied, “Seventeen.” I asked, “Which of these was the first?” He replied, “Al-`Ashira or Al-
`Ashiru.”