“You shall love your neighbor” (Matthew 5:43)  

Perhaps the man next door has more money than you do, and every day it bothers you that God has blessed him with wealth while you struggle financially. The feelings you have toward him are not godly. You know intuitively, because you're a new creature in Christ, that bad feelings toward someone is an indication you must go to God and ask forgiveness, and learn what’s wrong with your attitude. If you love your neighbor, you won’t envy what he has, even if, according to the world’s standards, he’s your enemy (Matthew 5:44). 

 This is where Christian salvation is categorically different from man-made religion. “Therefore you shall be perfect, just as your Father in heaven is perfect”(Matthew 5:48) is a command. Christ purchased for you the ability to love unconditionally. “Our gospel did not come to you in word only, but also in power, and in the Holy Spirit and in much assurance” (1 Thessalonians 1:5). If God has regenerated your heart and filled you with the Holy Spirit, you not only know from Scripture that Christ commanded you to love your enemy, He’s given you a new heart and the indwelling Holy Spirit, so you have the ability to love your enemy.

 Perhaps you know all this, but reason, "I can’t love my enemy, because while I treat him as a friend, he will not repent of his sin”. Now you can see the truth in all its glory. You’re not God. Only God can condemn to Hell. You’re commanded to pray for his salvation, not consign him to Hell. Christ commanded, “bless those who curse you, do good to those who hate you, and pray for those who spitefully use you and persecute you” (Matthew 5:44). If you can’t do this, you’re not saved. But if God has given you the ability to love your enemy, “to him who knows to do good and does not do it, to him it is sin” (James 4:17). 

 By the way, praying for your enemy will give you sympathy for him, and God will be much more likely to use you to open his eyes to the Gospel. Sinners know intuitively if you love them. If your enemy knows you care for them, and not just because you’re obeying Scripture, he’ll be be more likely to listen to what you say. “Do not be overcome by evil, but overcome evil with good” (Romans 12:21).