Does the noble verse: "Not equal among you are those who spent before the conquest and fought, those are greater in degree than those who spent afterwards and fought. But to all has Allah promised the best" mean that whoever comes after the era of the Companions will not attain their ranks in Paradise, even if they strive in obedience and worship?

There is nothing in the verse that calls for sadness, as it gave glad tidings to those who came first and those who came after them of good. The virtue of accompanying the Prophet, peace and blessings be upon him, is unmatched. However, there are glad tidings for those who hold firm at the end of time. The duty is to be keen on acts of obedience and to follow the Companions with excellence to attain Allah's pleasure.