What are some arguments for the doctrine of the trinity being necessary to understand the God of Christianity?

Interprets monotheism in the light of a specific set of events that happened in Christian Scripture. Not just an abstract belief, plays a central part in the worship of all mainstream traditions, example: baptism is carried out 'in the name of the Father, the Son and the Holy Spirit. It sees God as a community of three people coexisting in a coequal relationship of eternal love, this provides a model for human relationships