Challenged by a Jehovah’s Witness heckler to defend the doctrine of the Trinity from Scripture, J.I. Packer argued along the following lines:

Jesus:

1. endorsed Old Testament monotheism (Mark 12:29), yet,
2. regarded himself as ‘the Son’ in a unique sense (Matt. 11:27; Mark 12:1-12; 13:32), and prescribed and accepted worship of himself as Son of God, treating this as a proper expression of faith (John 5:23; 9:35-38; 20:28); and,
3. promised the Holy Spirit as ‘another Comforter’ in succession to himself, to carry on his own manysided ministering role (John 14:16); and,
4. bracketed Father, Son and Spirit together as the triune ‘name’ (singular, note, not plural) into which — that is, into a relationship with which — future disciples were to be baptized (Matt. 28:19).

God’s Words, p43