In Philippians 3:2 speaking against the Jews and Judaizers the apostle said "Beware of dogs!" He then contrasts true Jews (Christians) with false ones (of the flesh), and true circumcision (of the heart) with false (of the flesh). It is obvious Paul is convinced Old Israel is passing away. He uses one of the most derogatory terms, dog, to describe his "kinsman according to the flesh." Where once that term was used by Jews to describe Samaritans and Gentiles it has now been turned on them.
Is it possible Paul’s use of "dog" became a technical by-word among the Christian community to refer to the Jews. This may have been the case. If so, consider this in the light of Revelation 22:15.
Revelation is unequivocally a contrast between two cities: Babylon, "where our Lord was crucified" 11:8, and the New Jerusalem. It is a contrast between two women, one a bride adorned with righteousness for her husband and one dressed in scarlet and guilty of adultery. It is a contrast between two creations, one old, one new. It is a contrast between an old people and a new people, Revelation 2:9; 3:9; those who claim they are Jews, but are liars, and the real Jews, Jesus’ people.
In Revelation 18ff we find the destruction of Babylon, the city drunken with the blood of the saints and prophets, vs. 24. (Compare Matthew 23:34ff.) In chapter 21-22 we find the new Jerusalem. And who is outside the New City of God? "Outside are dogs…,"
Now given the obvious conflict between Christianity and Judaism in Revelation is it not extremely likely John is using the word "dog," a word once used by Israel to describe everyone outside their covenant, to signify Israel’s rejection and exclusion from the New Jerusalem? It fits the view of Matthew 8:11ff, Galatians 4:22ff and other texts which depict Israel being cast out of the kingdom. If this is the case, this would serve as supporting evidence for the early date of Revelation.