From Abbot Anscar Vonier, O.S.B. (died 1906):
It is a certain truth that if God in his providence exterminated every evil deed at once, killed every evil-doer, the final sum of goodness would be less. We have our Lord’s own words for it; there would be diminution. Goodness itself, sanctity itself, is fostered by the proximity of evil. As Saint Augustine puts it so well: it pleased God to make good come out of evil rather than to abolish all evil. God could have abolished all evil in his omnipotence; he did not; he did the better thing; he made good come out of evil, he makes sanctity come out of it; makes martyrs through the cruelty of man, and gives his Church the most glorious traditions of fortitude and courage through the very presence of enemies in her midst and around her walls. When the great day of harvest comes sanctity will be found to be so great and so high by very reason of the wickedness that encompassed it.
Our lives are constantly bound up with those of other people in some way or another. Perhaps those people fail in many things, but they are in some way a portion of our own lives; they partake of the graces we possess. “The faithless husband,” says Saint Paul, “will be sanctified through the believing wife.” The children of believers are sanctified through the very fact of their paternity. One person in a family may be the salvation of the whole family, though it may not be given to him to see the final issues and the ultimate results. But there is the fact – an absolute certainty, goodness inevitably produces goodness; it is unconquerable, it cannot be stifled, it has greater ramifications than evil can ever have… One saint outweighs a hundred, a thousand, perhaps a million sinners. The sanctity of one saint prevails over the sinfulness of a thousand sinners. Sin is negative; sanctity, positive. Sanctity is more powerful than sin; sanctity is, in fact, the only real power.