This chapter seeks to contribute to discussions regarding religion and racial capitalism by showing how particular economic practices, such as gambling, are linked to processes of social differentiation that are legitimized by a belief in luck. I analyze how horserace gambling held during Catholic patron saint festivities in the Sierra Mazateca of Oaxaca (Mexico) produces a language that expresses the antagonisms present in different spheres of society: between regions or families, the rich and the poor, and men and women. The ethnographic study of sixteen horseracing events that I observed in the Sierra Mazateca between 2009 and 2023 shows that, though they seem to be determined by the appreciation of the natural qualities of animals, gambling bets conceal an evaluation of the social characteristics of the person who takes its horse to the racetrack. The results of the races are explained not only by the biology of the horses or the skills of their trainers but also by the intervention of “luck”. Despite the obvious differences that distinguish people who face each other in bets, all gamblers are vulnerable to “misfortune”. The racecourse is therefore an arena in which social inequalities are recreated and legitimated, but the uncertainty essential to these games also allows them to be challenged, if only for a moment.