The Apparition that we will cover next week will the Church approved Apparition in Knock, Ireland. It was a silent Apparition and did not only include Mary, but also St. Joseph, St. John the Evangelist, and a Lamb on an altar with a Cross behind the altar.
The Apparition took place after the parish priest had done 100 days of masses for the souls of those people that weren't able to receive their last rights, or what we call now Anointing of the Sick. The vision is seen as a way of God telling those in Knock that the prayers have been heard. It is important to note that the Church teaches that, "God is bound to the Sacraments, but not by them." Meaning He is bound to them because He has said that He will do what He says He will do and God ALWAYS keeps up His end of the covenant, it's part of Who God IS to keep His Word.
He is not bound by them means that God can save people even if they do not receive the Sacraments, because again, He is God and can do anything He wishes to do.
Another way of stating the above would be, "God's Mercy flows through the Sacraments, but not only through the Sacraments but through all of His redemptive Creation."