They have faith in God and the Day of Judgment, do good deeds, avoid bad deeds and urge others to do good as well. These are among the good people of the world.
The Holy Quran says about them:
“Yet they are not all alike. There are among the People of the Book an upstanding nation that recite the verses of God throughout the night and prostrate themselves. They believe in God and the Day of Judgment. They command people to follow good, prohibit others from committing evil and compete with each other in doing good deeds. These are the righteous ones. And whatever good they do, they shall not be denied it, and Allah knows those who guard (against evil).” (Verses 113-115 of Surah Al Imran)
Like Muslims, the People of the Book are not all the same in terms of religiosity and Taqwa (God-fearing). Many of them recite the divine book and contemplate divine signs and whenever they faith the truth, they submit to it, which is the true meaning of prostration.
They also do good and avoid evil call on others to do the same and this is the essence of Islam and all divine faith and the prerequisite for salvation in this world and the next.
Professor William C. Chittick, a contemporary scholar and researcher who studied about the Iranian culture, literature and mysticism, once discussed the issue of Jesus (AS) being a Muslim in one of his speeches.
In the Holy Quran, many divine prophets have been described as Muslim. For example, in Verse 72 of Surah Yunus, Noah (AS) tells his people: “If you turn away from my preaching, it will not harm me; I shall receive my reward from God who has commanded me to become a Muslim.”
Also in Verse 84 of the same Surah, Moses (AS) is quoted as saying: “If you have submitted yourselves to God and have faith in Him, put your trust in Him.”
And there is also Verse 90 of this Surah: “We brought the Children of Israel through the sea, and Pharaoh and his legions pursued them arrogantly and frantically. But as he was drowning he cried out: ‘(Now) I believe that there is no god except He in whom the Children of Israel believe. I am of those that surrender (Muslims).’”
What is surprising is that sometimes a Muslim converts to Christianity and fails to understand that Islam also contains Christianity as the Quran says: “(They) have faith in what has been revealed to you and others (other prophets) before you and have strong faith in the life hereafter.”