...baptizing them in the name of the Father,
and of the Son, and of the Holy Spirit....
Historians of the Church tell us these final words from Jesus as he ascended into heaven -- a very clear indication of the Trinity -- developed first into the baptismal formula which we still use, and then into the creeds, the Apostles, Nicene and Athanasian.
The word Trinity does not appear in the Bible and is not a name of God. It is rather a beautiful teaching which helps us to understand the relationships of the Father, the Son and the Holy Spirit to one another and to us, without explaining that which is beyond human comprehension.
Because Jesus told us to "baptize them in the name..." we don't readily recognize any other formula. In the New Testament the only alternative is "in the name of Jesus" but, typically of Christians, there is a lot of controversy around it.
Some theologians have suggested an alternative like "in the name of the Creator, Redeemer and Sanctifier" but these proposals fall flat for many reasons. For one, those works belong to Father, the Son and the Holy Spirit. When we name the Father as the Creator of All we do not imply that Jesus and the Holy Spirit did not create the universe. The Father and the Holy Spirit redeem us; and the Father and the Son sanctify us. Secondly, the Bible will be around a thousand years from now, long after late-arriving bogus formulas have disappeared. We don't try to improve on the Bible.
On this feast of the Ascension we celebrate the man we have known, one of our own children, Jesus of Nazareth, son of Mary, who has been given and has taken his appointed place at God's right hand. This is a wonder and delight; that a human being is the Son of God. He is not adopted in the sense that there was a time when he was not the Son of God. He was always, from before eternity, the Son of God; by his death and resurrection and ascension he has been revealed to us. This was beyond our imagination and comprehension. We would not believe it if we had not seen it. No one could have dreamed this up.
Many would refuse the title to him. They think God should not do it; or they simply deny that God exists in any form, human or divine. They refuse to take our word for it. They might believe many things people tell them but they won't believe that. Their skepticism certainly causes us sadness and grief; it might even force us to rethink our beliefs. But we keep coming back to what we have seen and heard, and what the Spirit of Truth has reaffirmed in our hearts. As Isaiah said, "Who would believe what we have heard?"
Their skepticism and the doubts that abide in our hearts -- Saint Matthew says "When they saw him, they worshiped, but they doubted." -- only urge us to deeper prayer. We have found peace, satisfaction, joy, generosity, courage and solidarity through our practice of faith; we cannot surrender such gifts for a few lingering doubts that only lead to perdition.