The purpose of revelation of this verse also explains this...

The purpose of revelation of this verse also explains this subject in a complete way that, after the apostleship of the Holy Prophet and the revelation of Holy Quran some Muslims will think that, when Islam is the only way of truth and salvation, then what will be the fate of our ancestors, who were the followers of other religions at that time? The noble verse was revealed to assuage them.

Surely those who believe, and those who are Jews, and the Christians, and the Sabians, whoever believes in Allah and the Last day and does good, they shall have their reward from their [1] And they became deserving of Allahs wrath; this was so because they disbelieved in the communications of Allah and killed the prophets unjustly; this was so because they disobeyed and exceeded the limits. (Surah Baqarah 2:61) Lord, and…