Competition is that no less indomitable humanitarian force that wrests progress, as fast as it is made, from the hands of the individual and places it at the disposal of all mankind.
After announcing that competition is beneficial to individuals, including those at the lower end of the social ladder, Frédéric Bastiat explains why this is so. The reason he identifies is that it is a way to rebalance self-interest.
Adam Smith had identified self-interest as an essential engine of the economy and had attributed this to the invisible hand. As a matter of fact, it first appears paradoxical that self-interest can be an engine for general interest. What Frédéric Bastiat is explaining here is that competition plays an essential role in the transition from the former to the latter and describes personal interest as something that would tend to create monopolistic injustice but is curbed by competition, which reduces nuisances that could be created in the name of self-interest.