The word trinity does not appear in the bible.  But there are references throughout the bible.  In Genesis God the creator works through the Spirit and speaks the Word of Creation.  In John, Jesus is the visible presence of God, while the Spirit is the invisible presence of God.  In the Romans passage, we have peace with God through Jesus, and hope through the Holy Spirit.  In the new Jerusalem of Revelation, Christ and God are seated on thrones in the temple, while the river of the Spirit flows from it.

We don’t understand how Christ could be fully human and fully God, nor how the Spirit is both, but we do have one God

Confession

Holy God, you reveal yourself to us in Scripture, but we still only get glimpses of Your majesty and Your glory.  We want to make you more understandable, so we try to limit Your power to ways we can understand.  We imagine You as a human being, since we are made in Your image, but we forget that You are infinitely more than we can understand.  Help us to gain more understanding of You, and the wonder of Your love.