A rigorous, fair-minded analysis of this problem which is too sublime for this lot is provided by John J. Collins in
Love Your Neighbor: How It Became the Golden Rule:
... The most striking innovation in the Gospels, exceptional in ancient literature, is the command to love one’s enemies, which is framed as an expansion of the laws in Leviticus. ... it is clear that Jesus is speaking only to Jews. ... “enemy” likely refers to “enemy Jews.” ... That Jesus is referring to actions rather than feelings is even clearer in Luke than in Matthew, as he adduces practical examples such as charity, praying for one’s enemies, and allowing them to abuse you.
The command to love one’s neighbor as oneself is undoubtedly one of the great contributions of the Hebrew Bible to the ethical development of humanity. In context, the law was primarily concerned with the cohesion and identity of a particular people, yet the application of the “neighbor” would in time be extended to all people, and grounded in the recognition of shared humanity.
This "enemy Jew" interpretation is consistent with an interpretation of the historical Jesus which recognizes that the gospel for the Gentiles was not original with him, but was a development which was driven by the converted Pharisaic representatives of Hellenistic Judaism.
