Today we celebrate the Solemnity Of The Most Holy Trinity.
In the Holy Trinity we have a God in three persons: the Father, the Son, and the Holy Spirit.
Need a refresher on where this doctrine came from?
Ok, here’s a quick excerpt from Rev. William G Most in The Basic Catholic Catechism...
“We came to know this immense mystery because Christ revealed it to us. Just before ascending He told them: "Go teach all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit" (Matthew 28:19). We know that these Three are not just different ways of looking at one person. For at the Last Supper, Jesus told us: "I came forth from the Father." So He is different from the Father. But He also promised: "If I go, I will send Him [the Paraclete] to you. . . . He will guide you to all truth" (John 16:28, 7, 13). So the Holy Spirit is also different.”
The Feast Day itself (not the doctrine) got it’s start in the fourteenth century by Pope John XXII and has progressed and changed over time into what we see today.
Happy Feast Day!