No Enemies
This final antithesis is the first to begin with a quotation not entirely from Scripture. “Love your neighbor” comes from Lev 19:18, but “hate your enemy” appears nowhere in the Old Testament. Commentators debate whether or not this latter command is a legitimate inference from texts like Deut 23:3–6; 25:17–19; or Ps 139:21, but hatred of enemies was common enough in subsequent generations so as to fit under the category of something Jesus’ audience had “heard that it was said”
Again Jesus opposes the traditional teaching and enunciates a more demanding ethic. Christians must love their enemies (v. 44). Otherwise they are no different than tax collectors and pagans, two groups classically despised by orthodox Jews—the first for working for Rome in collecting tribute from Israel and the second because of their false religion
Almost all people look after their own. The true test of genuine Christianity is how believers treat those whom they are naturally inclined to hate or who mistreat or persecute them. Whatever emotions may be involved, “love” here refers to “generous, warm, costly self-sacrifice for another’s good.” “Greet” (v. 47) refers to more than a simple hello, namely, heartfelt “expressions of desire for the other person’s welfare.” People who so love and greet their enemies and pray for their persecutors thus prove themselves to be those, as in v. 9, who are growing in conformity to the likeness of their Heavenly Father
Jesus’ followers must thus demonstrate a higher moral standard than the average unbeliever. A second rationale for loving one’s enemies is that God loves them too. Among other ways, he demonstrates that love through common grace for all humanity in his good provisions in nature (the sun shining and rain falling, v. 45). “What reward will you get?” (v. 46) parallels “What are you doing more than others?” (v. 47), suggesting not the idea of compensation for doing good but the recurrent theme of the believer’s distinctiveness.
Perfect” here is better translated as “mature, whole,” i.e., loving without limits (probably reflecting an underlying Aramaic tamim). Jesus is not frustrating his hearers with an unachievable ideal but challenging them to grow in obedience to God’s will—to become more like him