往生集 3.31

3.31

贊曰。至心念佛一聲。滅八十億劫重罪。此其明徵乎。所以者何。至心故也。若匪至心。罪則不滅。毋曰聖訓之無稽哉。

The appreciation says: Recalling the Buddha once with utmost sincerity eradicates grave transgressions of eighty billion kalpas—is this not clear proof? Why is this so? Because of utmost sincerity. If it is not done with utmost sincerity, transgressions are not eradicated. Let it not be said that the holy teachings are without evidence!