From my recent paper ("St. Paul on Jesus Christ, 'Our Great God and Savior'"):
St. Paul directly gives the name "God" to Christ in several places. He exhorts the elders of Ephesus "to shepherd the Church of God that He obtained with His own Blood" (Acts 20:28; qtd. in Prat). Early Patristic witnesses to this reading include Sts. Jerome ("Letter 54:4 to Furia") and John Cassian ("On the Incarnation" 7:4). St. Jerome's witness is not to be taken lightly!
The "Letter to the Hebrews" contains highly explicit testimony to the full divinity of the Son. When St. Paul elaborates on the superiority of Christ to even the highest choirs of the angels, he declares that God the Father calls His Only-Begotten Son by the name of God: "But of the Son He says, 'Your throne, O God, is forever and ever, and the righteous scepter is the scepter of Your Kingdom'" (Hebrews 1:8).
Finally, to stress the full divinity of Christ in the most explicit terms, St. Paul tells St. Titus that "we wait for the blessed hope and manifestation of the glory of our great God and Savior, Jesus Christ" (Titus 2:13; qtd. in Prat). This παρουσία on "the day of the Lord will come like a thief in the night" (1 Thessalonians 5:2).
- Prat, Ferdinand. "St. Paul." The Catholic Encyclopedia. Vol. 11. New York: Robert Appleton Company, 1911. 7 May 2010 <http://www.newadvent.org/cathen/11567b.htm>.