After it is all over, the religion of man is his most important possession.

The line contrasts worldly achievements with what remains when life’s contests—wealth, status, power—have “all” passed away. It suggests that, in Rockefeller’s view, religious faith is not merely a private preference but the most enduring form of capital: a framework for meaning, moral accountability, and hope beyond material success. Read this way, the quote functions as a summative judgment on priorities, implying that the final audit of a life is spiritual rather than financial. It also reflects a common late‑19th/early‑20th‑century Protestant ethic in which personal religion underwrites character and guides stewardship, especially for those with great wealth.