The law commanding love for one's neighbor is found in Leviticus 19:18, but the law to hate one's enemies is not found explicitly in God's word. However, the Hebrews were forbidden to make peace with the people of Canaan (cf. Exo. 34:11ff; Deut. 7:1ff), and the bloody wars which were waged by God's own command inevitably taught them to hate their enemies. This was even the feeling of their most pious men (e.g., II Kings 13:19).
In contrast, Jesus desires His disciples to practice love rather than revenge. He wants us to have a selfless concern for the ultimate good of others. He wants us to love our enemies, not in an emotional sense which would be impossible, but in the sense that we seek what is in their best interest. It is in this manner that we can and must love our enemies. Jesus' life perfectly illustrated this principle of righteousness. Some other notable examples in the Scriptures include: Luke 10:25-37, Acts 7:60, and I Samuel 24:13.
We love our enemies when we bless them, do good to them, and pray for them. These things are not possible if hatred resides in our hearts. Even if these activities do not change them, they will help us develop love like God's. Truly, this is how one should properly respond to persecution.
Reflecting upon Matthew 5:45 should deepen one's sense of awe concerning divine love. God bestows blessings abundantly upon all, both the good and evil. He makes His sun rise and He sends rain. Does it not seem incredible that a Being would be so generous, even to those who hate Him or deny His existence? It sounds unbelievable from man's perspective, but that is the depth of God's love (cf. John 3:16; Romans 5:8)! Let us imitate His type of benevolence (Luke 6:35)!
Our Lord continued in Matthew 5:46-48 by saying - "For if you love those who love you, what reward have you? Do not even the tax collectors do the same? And if you greet your brethren only, what do you do more than others? Do not even the tax collectors do so? Therefore you shall be perfect as your Father in heaven is perfect."
If we only love those who return our love, how are we any better than the tax collectors? Tax collectors were not highly regarded in Jesus' day for several reasons: (1) The Jews, being a subjugated people, paid taxes to the Romans, and this made the taxes especially distasteful, (2) The Jews who worked as tax collectors for the Romans were considered by their brethren to be traitors, and (3) The men who would work at such a position were often guilty of fraud or extortion (e.g., Luke 19:7,8). Jesus' point is that our religion is worth little if it doesn't lead us to a higher love than that which is shown by worldly men (cf. Prov. 24:17). Our love should not be restricted simply to those who are like us. We should greet everyone in a kind manner, seeking opportunities to do good for all (Gal. 6:10).
In context, to be perfect like the heavenly Father refers to having a perfect love like God's--a generous, merciful love (cf. Luke 6:36). Although man is to be perfect, he will never be sinless (I John 1:8-10). To be perfect is to be complete, whole, mature, or full-grown. Our goal is to become full-grown in the attribute of love as God is. He is our standard, not men. We will find completeness when we love everyone, return good for evil, pray for all, and do more than is required of us.
Friends, do you love your enemies? Are you seeking what is in their best interest? You must if you want to be true children of God and unlike the world!