44 But I tell you, Love your enemies and pray for those who persecute you,
45 To show that you are children of your Father Who is in heaven; for He makes His sun rise on the wicked and on the good, and makes the rain fall upon the upright and the wrongdoers [alike].
46 For if you love those who love you, what reward can you have? Do not even the tax collectors do that?
47 And if you greet only your brethren, what more than others are you doing? Do not even the Gentiles (the heathen) do that?
48 You, therefore, must be perfect, as your heavenly Father is perfect [that is, grow into complete maturity of godliness in mind and character, having reached the proper height of virtue and integrity].
(Matthew 5:43-48). [Amplified Bible].
43 The command "Love your neighbor" is found in Lev 19:18; no OT Scripture adds "and hate your enemies," though this seems to be the result of popular reasoning. Such reasoning seems to have said that if God commands love for "neighbor," then hatred for "enemies" is implicitly conceded and perhaps even authorized.
44-47 Jesus allowed no casuistry. The real direction indicated by the law is love, rich and costly, and extended even to enemies. Many take the verb and the noun "love" as always signifying self-giving regardless of emotion, but such an interpretation is unwarranted. The content of Christian love is not based on a presupposed definition but on Jesus' teaching and example. To love one's enemies, though it must result in activities such as doing them good (Lk 6:32-33) and praying for them (Matt 5:44), cannot justly be restricted to activities devoid of any concern, sentiment, or emotion. There is no reason to think the verb here in Matthew does not include emotion as well as action.
The specific "enemy" referred to here is one's persecutors. Jesus himself repeatedly warns his disciples of impending persecution (e.g.; vv. 10-12; 10:16-23; 24:9-13). If Matthew's first readers were being persecuted for their faith, that was doubtless one application they made.
Jesus' disciples have as their example God himself, who loves so indiscriminately that he sends sun and rain on both the righteous and the unrighteous. Yet we must not thereby conclude that God's love toward people is in all respects without distinction, and that therefore all will be saved (see Matt 25:31-46). Theologians call this love of God his "common grace" (i.e., the gracious favor God bestows "commonly," without distinction, on everyone).
God's example provides the incentive for Jesus' disciples to be "sons of [their] Father" (v.45). Ultimately this clause points to the necessity pf pursuing a certain kind of sonship patterned after the Father's own character. Jesus' disciples must live and love in a way superior to the patterns around them. Jesus goes on to point out that even the despised tax collectors love those who love them; Christian love must go beyond what naturally takes place.
48 It is best to understand v.48 as the conclusion to all the antitheses. The OT background to this verse is Lev 19:2, with "holy" displaced by "perfect". Here for the first time perfection is predicated of God.
In light of the preceding verses (vv.17-47), Jesus is saying that the true direction in which the law has always pointed is not toward mere judicial restraints, concessions arising out of the hardness of human hearts, still less casuistical perversions, nor even the "law of love." No, it pointed rather to all the perfection of God. exemplified by the authoritative interpretation of the law bound up in the preceding antithesis. This perfection Jesus' disciples must emulate if they are truly followers of him who fulfills the Law and the Prophets (v.17).
[NIV BIBLE COMMENTARY Volume 2: New testament].
JESUS IS LORD.