In the future, when He sits on the seat of justice, viz. "for all of His ways are justice." In the future, when He sits in judgment with each one, He gives him what he deserves. "He is a G-d of trust": Just as He rewards an absolute tzaddik in the world to come for the "lightest" mitzvah that he performed in this world, so, He "rewards" an absolute evildoer in this world for the lightest mitzvah that he has performed. And just as He punishes an absolute evildoer in the world to come for a transgression that he performed in this world, so, He punishes in this world an absolute tzaddik for a transgression that he has performed.