Jesus said to his disciples: "If your brother sins against you, go and tell him his fault between you and him alone. If he listens to you, you have won over your brother."
Gospel's Commentary
Today Jesus speaks to us about fraternity. No one should go alone in life, and least of all we Christians. This is why we must help ourselves, by having even the courage to gently correct those who are wrong and/or accepting them to correct us.
It is said that "union is strength." But imagine if, in addition, "where two or three are gathered together in my name, there am I [Jesus]". By having Him in the "team", we will get from His Father everything we may ask for.