This passage, found at John 17:11, is one option for the Communion Antiphon for the daily Mass this week. Today, in reading this verse in preparation for receiving the Eucharist, Jesus’ call struck me in a profound way. I have studied the Holy Trinity in the past (I took a course on it in grad school and taught a class on it earlier this year). We can certainly say something about God as three Persons. But as the early triinitarian controversies and lengthy treatments (witness Augustine and Aquinas among many others) of this matter show us, it is a subject that can be plumbed to infinite depths and a concept of which our darkened human intellects can only conceive in a limited way.
All that being said, one certain thing we can take away from our understanding of God and Three and One is that this oneness is complete. Three Persons, One divine nature. Jesus elsewhere says, “Whoever has seen me has seen the Father…Do you not believe that I am in the Father and the Father is in me?” (Jn 14:9-10) While we cannot comprehend this completely now, and hope to have the chance, by God’s grace, to contemplate Him for all eternity, we know from the Lord’s own words that there is a relationship unique here in all reality. And we are asked to approach this relationship with each other!
Now, as baptized Christians we are incorporated into the Body of Christ. “One” is the first mark of the Church our Savior established (cf. Mt 16:18). Division comes from the devil. Should we not want to follow Jesus’ command to be one with all our fellow human beings? Solidarity among Christians in faith and practice — living the true faith in our relationship to God and man — is something for which we must continue to strive. Never should we give scandal because we who profess to be Christians do not provide good example.
This ties in directly to evangelization. Ecumenical efforts (i.e., among Christians) and interreligious dialogue (i.e., among those of different religions) should strive to bring everyone to the fullness of truth so that all humankind can truly “be one.” We are to continue to work and pray to see the day when every person can say the Lord’s Prayer from the heart (“Our Father”) and thus bring forth God’s reign (“thy kingdom come”).