Trinity Sunday is the hinge on which the entire Christian liturgical calendar year swings. The first half of the year (Advent, Christmas, Epiphany, Lent, Easter, Ascension, Pentecost) culminates in Trinity Sunday. The second half of the year (the season after Trinity) unfolds from that same day.
In the modern Revised Common Lectionary, used in slightly differing variations by Roman Catholics, Episcopalians, Lutherans, and many Presbyterians and Anglicans throughout the world, the season after Trinity Sunday is completely different. In that new calendar most the scripture readings essentially walk sequentially through the Bible independent of one another. So while there is a season-wide progression in the reading-the-Bible sense, there is no overall plan of topical coverage or discipleship, like the other calendar seasons have.
In the traditional calendar and lectionary (which was used in various forms from the 500’s until about the 1970’s), there was a very definite and intentional plan for discipleship through the season after Trinity Sunday. It, too, did feature a progressive walk through some of the New Testament epistles for much of the season, but a many-layered approach to spiritual formation was also quietly included. As my church (along with a significant minority of other local Anglican churches) is using the traditional calendar, I thought it would be helpful, for us and others, to have an introduction to what this liturgical season is all about.
As previously described, Trinity Sunday culminates the first half of the year by introducing God for what he is: the Three-in-One and One-in-Three. Simultaneously, it launches the entire season that follows (ending with the Sunday before Advent). The first and second Sundays after Trinity Sunday unpack this identity of God by reflecting on the fact that both God and his first commandment are summed up as love.
The rest of the season applies this basic identity and commandment of love to the Christian life in a long intentional discipleship course. It follows three stages, traditionally identified as purgative, illuminative, and unitive. Each of these stages are seven weeks long and each deal with the same issues of the human mind, the human heart, and the human desire.
Stage 1: Purgation is about dealing with the power of sin within us. The 3rd & 4th Sundays are about purging our minds, the 5th-7th Sundays are about purging our hearts, and the 8th & 9th Sundays are about purging our desires. Once the power of sin is has been thoroughly addressed in this way, we move on to the next stage.
Stage 2: Illumination is about dealing with presence of sin within us. The 10th & 11th Sundays are about illuminating our minds, the 12th-14th Sundays are about illuminating our hearts, and the 15th & 16th Sundays are about illuminating our desires. Where the purgative stage focused on purging the power of sin, the illuminative stage focuses on highlighting the sinfulness that wells up within our own fallen nature. With that completed, the final stage is up.
Stage 3: Union is about dealing with the remnant of sin within us. The 17th & 18th Sundays are about uniting our minds with God, the 19th-21st Sundays are about uniting our hearts with God, and the 22nd & 23rd Sundays are about uniting our desires with God’s. Where purgation was about removing sinfulness from ourselves and illumination was about revealing the sinfulness that naturally seems to crop up in us, union is about shedding the last vestiges of that sin nature and becoming one with God in Christ.
This all comes to a head on the 24th Sunday after Trinity Sunday, which celebrates the resurrection and wholeness promised to all God’s people. The goal of the entire Christian life is be converted from the deathly powers of sin to the eternal life-giving power of God. Of course, everyone is at a different point in this journey. So rather than teaching down to the slowest student (as often ends up happening in school classrooms these days), the season after Trinity Sunday walks all Christians through the whole curriculum so they can see each year where they’ve been, where they are, and where they’re going.