1. The Trinity is not an optional doctrine, it is essential. God’s unity is not behind God’s threeness, God’s unity is in God’s threeness. This is not speculative mathematics, it is a descriptive theology of revelation.
2. The Trinity is not an academic doctrine thought up by clever scholars, rather it grew out of the Christian experience of worship, i.e. it expressed the early church’s pattern of prayer tothe Father, through the Son, in the Spirit.
3. The driving force of the development of the doctrine of the Trinity was Christological and soteriological, i.e. it served to articulate the Christian experience of salvation in Christ. The first Christians already knew God; through Jesus they came to know God as Jesus’ Father and Jesus as God’s Son; while in the Spirit Jesus continued to be present to them, forming a family of prayer to the Father and building a community of witness to Christ.
I. HOW TO AVOID TRINITARIAN HERESY
#1. Start by abolishing Trinity Sunday, that fateful day on which preachers think they have to explain the Trinity
#2. Teach children to make the sign of the cross when they say the words “Father, Son and Holy Spirit”
#3. When someone offers to tell you the practical implications of the doctrine, just smile and move along
#4. Have you come up with a really helpful analogy of the trinity? Well done! Now please don’t tell anyone about it, ever
#5. The doctrine is not a mystery. It is simple & precise. The reality it points to is the mystery
#6. Don’t try to get rid of the biblical words. Don’t try to stick to them exclusively either
#7. In this doctrine every word is used in a very limited way. Even the numbers 1 and 3 can’t be taken literally
#8. Don’t partake in meaningless debates about whether “oneness” or “threeness” is more important (see #7)
II. TRINITARIAN THEOLOGY, EAST AND WEST
#9. Don’t worry about whether you prefer Augustine or the Greeks. You don’t have to pick a favourite, it’s not Masterchef.