Lenz’s law states that the polarity of the induced voltage in a coil of wire in response to a time-varying flux is in such a way that if a load is connected across the terminals of the coil, a current will flow which leads to a flux that opposes the change in the original flux with respect to time.
In fact, the induced voltage (the effect) opposes the change with respect to time in the flux that generated it (the cause). This is the reason why a negative sign appears before the magnitude of the induced voltage in Faraday’s Law.