Those who set out to serve both God and Mammon soon discover that there is no God.

Smith’s aphorism riffs on the biblical opposition between God and “Mammon” (wealth, worldly gain). It suggests that trying to keep religious devotion while simultaneously making material success the governing aim produces a spiritual hollowing-out: the compromises required to “serve” both end by displacing God altogether. The sting is not merely moralistic (greed is bad) but psychological and cultural: once faith is treated as one interest among others—balanced against profit, status, or comfort—it ceases to function as an ultimate commitment. The line also reads as a critique of respectable religiosity that baptizes self-interest, implying that such double service leads not to divided loyalties but to practical atheism.