Zayd bin Arqam (may Allah be pleased with him) took part in seventeen military expeditions with the Prophet (peace and blessings be upon him)

Abu Ishaq states: The people went out for the prayer for rain (istisqa'), and among them was Sayyiduna Zayd bin Arqam (may Allah be pleased with him); there was only one man between him and me. I asked him: "O Abu Amr! How many military expeditions did the Prophet (peace and blessings be upon him) undertake?" He replied: "Nineteen." I asked: "In how many did you yourself take part with him (peace and blessings be upon him)?" He said: "Seventeen."
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim).

It is narrated from Sayyiduna Zayd bin Arqam (may Allah be pleased with him): We set out with the Messenger of Allah (peace and blessings be upon him) until we reached the place of Ghadir Khumm. He (peace and blessings be upon him) ordered that a place be cleared under the shade of the trees. It was so intensely hot that day that we had never faced a hotter day than it. Then he (peace and blessings be upon him) praised Allah and extolled Him, and said: "O people! No prophet has ever been sent except that he lived half as long as the prophet who came before him. I think that soon I will be called (by my Lord) and I will respond. I am leaving among you something after which you will never go astray, and that is the Book of Allah, the Mighty and Majestic." Then he (peace and blessings be upon him) stood up, took hold of the hand of Sayyiduna Ali (may Allah be pleased with him) and said: "O people! Who has more right over you than your own selves?" They all said: Allah and His Messenger know best. He (peace and blessings be upon him) said: "Whoever I am the mawla (patron) of, Ali is also his mawla."
This hadith has a sahih (authentic) chain of narration, but the two Shaykhs (Bukhari and Muslim) did not record it.