Trinity Sunday is the first Sunday after Pentecost in the Western Christian liturgical calendar, and the Sunday of Pentecost in Eastern Christianity. Trinity Sunday celebrates the Christian doctrine of the Trinity, the three Persons of God: the Father, the Son, and the Holy Spirit.
Observance
On Trinity Sunday, the Christian Church ponders with joy and thanksgiving what the Father, Son and Holy Spirit have done to accomplish the salvation of sinful humanity. It is brought to remembrance how Christians should respond to the love God has shown for them, praising Him and giving Him glory.