Praise be Jesus and Mary, now and forever. 
Go show yourselves to the priests. It is God who forgives sins, it is God who cleanses us from sin, but he does so through the ministry of his priests, through the sacrament of confession.
There are three fundamental reasons to go to confession and to go to confession frequently. The first is to be freed from mortal sin and to be preserved from falling back into other mortal sins. The second is to be freed from venial sin and to be preserved from falling back into more deliberate venial sin. The third reason is to be freed from the anxiety of doubtful sins, from those situations where we are unsure. Did I commit a sin? Did I not commit a sin? Or did I already confess the sin? Did I not confess the sin? Is what I'm doing sinful or not sinful? Confession can free us from that anxiety, and in confession, our Lord wants to give us tranquility, peace of conscience. Whatever the reason, our Lord invites us to go to confession and to go frequently, at least once a month for those who want to really make spiritual progress and even more frequently than that if we are committed to holiness in earnest.
Third Order members, for example, MIM members, even more frequently than that so as to truly make that progress, make that growth in holiness. Go show yourselves to the priests, our Lord says. He wants to forgive us. God forgives, but he does so through the ministry of his priests and through the sacrament of confession. Praised be Jesus and Mary, now and forever.