The Holy Trinity | 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”…

Receive the Holy Spirit. 

Ascension of the Lord | "You will receive power when the Holy Spirit comes upon you, and you will be my witnesses in Jerusalem, throughout Judea and Samaria, and to the ends of the earth."