One of the common objections that people make about God’s providence and His goodness is the reality of evil in the world. How can it be, they ask, that God allows sin and evil to exist alongside His good creation? The key word in this is “allows.” As the first parable in today’s Gospel makes clear, sin and evil (the weeds growing among the wheat) exist not by the hand of God, but rather because “an enemy has done this.” Like the good wheat which must struggle to bear fruit while fighting against the weeds, we must struggle to live holy lives in a world infected with sin and evil. God intends for us to be saved, and so He gives us the strength necessary (through the Grace of the Sacraments) to persevere until the “harvest time.”
Another aspect of this question about the existence of evil involves the possibility of human freedom. If it were not possible for a man to choose evil, there would be no virtue in having chosen the good. Human freedom would not exist if it were not possible for us to choose one or the other. It is precisely the existence of human freedom – and the possibility of choosing good or evil – that warrants the praise of virtuous acts and the condemning of evil acts. Parents experience this simple principle when their child “who is old enough to know better” does something which is wrong. Out of respect for their child who is now able to make moral choices they show their displeasure. Conversely, when they witness their child doing something good it is right to give praise.
May God bless you!