interplay between Abraham on the one hand and the Lord/three men/the two angels on the other was an intriguing text for those who believed in a single God in three persons. Justin Martyr, and John Calvin similarly, interpreted it such that Abraham was visited by God, who was accompanied by two angels. Justin supposed that the God who visited Abraham was distinguishable from the God who remains in the heavens, but was nevertheless identified as the (monotheistic) God. Justin interpreted the God who visited Abraham as Jesus, the second person of the Trinity. Augustine, in contrast, held that the three visitors to Abraham were the three persons of the Trinity. He saw no indication that the visitors were unequal, as would be the case in Justin's reading. Then in Genesis 19, two of the visitors were addressed by Lot in the singular: "Lot said to them, 'Not so, my lord (Gen. 19:18). Augustine saw that Lot could address them as one because they had a single substance, despite the plurality of persons. Christians interpret the theophanies, or appearances of the Angel of the Lord, as revelations of a person distinct from God, who is nonetheless called God. This interpretation is found in Christianity as early as Justin Martyr and Melito of Sardis, and reflects ideas that were already present in Philo. The Old Testament theophanies were thus seen as Christophanies, each a "preincarnate appearance of the Messiah". The New Testament While the developed doctrine of the Trinity is not explicit in the books that constitute the New Testament, the New Testament contains a number of Trinitarian formulas, including Matthew 28:19, 2 Corinthians 13:14, 1 Corinthians 12:4–5, Ephesians 4:4–6, 1 Peter 1:2, and Revelation 1:4–5. Reflection by early Christians on passages such as the Great Commission: "Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit" and Paul the Apostle's blessing: "The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all", leading theologians across history in attempting to articulate the relationship between the Father, Son, and Holy Spirit. Eventually, the diverse references to God, Jesus, and the Spirit found in the New Testament were brought together to form the doctrine of the Trinity—one Godhead subsisting in three persons and one substance. The doctrine