The Oneness doctrine may be considered a form of Modalism, an ancient teaching considered heresy by most Christians. In contrast, Trinitarian Pentecostals hold to the traditional doctrine of the Trinity, that is, the Godhead is not seen as simply three modes or titles of God manifest at different points in history, but is constituted of three completely distinct persons who are co-eternal with each other and united as one substance. The Son is from all eternity who became incarnate as Jesus, and likewise the Holy Spirit is from all eternity, and both are with the eternal Father from all eternity.