Listed below are some of the major passages describing "our enemies" - the ones Jesus spoke of whom we should love. All passages quoted from the NKJV.
Matthew 10:36 - "And a man's enemies will be those of his own household."
This thought will probably startle some Christians. Our usual idea is to deal with "enemies" from the world around us, but not from our own families! But Jesus wanted His disciples to know some people have to make a decision of turning their lives over to Jesus or yielding to family pressure and not believing in Jesus. Anyone, including people of your own family, who try to keep you from believing in Jesus, become an enemy to your soul. However, you are still to love them and seek their salvation even though they are trying to keep that salvation from you!
Romans 5:10 - "For if when we were enemies we were reconciled to God through the death of His Son, much more, having been reconciled , we shall be saved by His life."
This verse reminds us that we were once enemies of God! But praise the Lord that other Christians loved us anyway and helped us turn our lives over to Christ!
Romans 11:28 - "Concerning the gospel they are enemies for your sake, but concerning the election they are beloved for the sake of the fathers."
This passage speaks of the people of Israel who rejected Gentiles as having any kind of favor with God. God still loves them and He wants us to treat them with love and seek their salvation. That's exactly what Paul did. See Romans 10:1 - "Brethren, my heart's desire and prayer to God for Israel is that they may be saved."
Philippians 3:18 - "For many walk, of whom I have told you often, and now tell you even weeping, that they are the enemies of the cross of Christ."
This passage does not necessarily only speak of unbelievers. The context of this passage in Philippians, suggest these people are indeed, believers who are not living their lives in harmony with the Gospel and bring shame to the name of Christ!
Colossians1:21 - "And you, who once were alienated and enemies in your mind by wicked works, yet now He has reconciled."
This passage, like Romans 5:10, reminds us where we all were before "Christ died for us." We were like aliens to God! We thought of evil and practiced evil, but God still reached out to save us and reconcile us back to God!
2 Thessalonians 3:14,15 - "And if anyone does not obey our word in this epistle, note that person and do not keep company with him, that he may be ashamed. Yet do not count him as an enemy, but admonish him as a brother."
Again, this speaks of believers who refuse to live their lives to honor and glorify the Lord. Note James 4:4, "Adulterers and adulteresses! Do you not know that friendship with the world is enmity with God? Whoever therefore wants to be a friend of the world makes himself an enemy of God." Christians can still show them love but they are not to have close fellowship with them and certainly not do as they do! Treat them as an unbeliever who needs to get right with God.