To attain happiness in another world we need only to believe something, while to secure it in this world we must do something.

The line contrasts the ease of promised, posthumous “happiness” in many religious frameworks—often conditioned primarily on belief—with the harder, practical work required to build well-being in lived society. It reflects Gilman’s characteristic emphasis on social reform, material conditions, and human agency: happiness is not a reward to be awaited but an outcome to be organized through action. Implicitly, the quote critiques complacency and the deferral of justice or fulfillment to an afterlife, urging attention to concrete responsibilities in the present—ethical conduct, collective improvement, and the restructuring of social arrangements that produce suffering.