Charles H. Spurgeon on Psalms 91:8

Only with thine eyes shalt thou behold and see the reward of the wicked. First, indeed, because of thy own escape; secondly, on account of thy complete security; thirdly, for the sake of comparison; fourthly, because of the perfect preeminence of justice itself. For then it will not be the time of mercy, but of judgment; nor shall any mercy in any way be ever shown towards the wicked there, where no improvement can be hoped for. Far away will be that softness of human infirmity, which meanwhile charity nevertheless uses for salvation, collecting in the ample folds of her outspread net good and bad fishes, that is, pleasant and hurtful affections. But this is done at sea. On the shore she chooses only the good, and so rejoicing with them that do rejoice, it hence comes to pass that she weeps not with those that weep. Bernard.