The Mystery of the Most Holy Trinity
 
A Mystery of Faith is a truth revealed by God, which we are bound to believe, even though it surpasses our comprehension. If we could understand every aspect of God, then He would not be God. 
 
The Most Holy Trinity is the mystery of one God in three persons, whoa re the Father, the Son, and the Holy Ghost.
 
The Father is God, the Son is God, the Holy Ghost is God, but all three, the Father, the Son, and the Holy Ghost are only one and the same God, equal in all things, because they are one and the same substance and consequently one and the same Godhead. 
 
Image Explanation
 
The Triangle in the Middle represents the Trinity. We can see God the Father, God the Son, and God the Holy Ghost. 
 
The Top Left Scene shows Christ just before He ascends to Heaven, charging His Apostles with the Mission to teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost. (Matthew 28:19)
 
The Top Right Scene shows Christ being baptized by St. John the Baptist in the form of the Trinity.
 
The Bottom Left Scene shows Abraham receiving the three angels. although three stood before him, he spoke as if to only one: "Lord, if I have found favor in your sight, pass not away from your servant." In this manner, he paid honor to one God in three Persons. 
 
The Bottom Right Scene shows the story of Saint Augustine. One day, he was walking on the beach contemplating the Mystery of the Trinity when he saw a small child. The child was fetching water from the sea with a shell and emptying it into a hole he made in the sand. St. Augustine asked, "What are you trying to do with this water, my child?" The child replied, "I want to put all the water of the sea into this hole." St. Augustine said, "But, you see, this hole is far too small to contain all that water." The child replied back, "Just so, but it is easier for me to empty the sea into this hole, than for you to understand the Mystery of the Trinity." The child quickly turned into an angel and vanished.