Israel was commanded to love those who were of the covenant people of God…
Leviticus 19:17-18 (ESV)
You shall not hate your brother in your heart, but you shall reason frankly with your neighbor, lest you incur sin because of him. You shall not take vengeance or bear a grudge against the sons of your own people, but you shall love your neighbor as yourself: I am the Lord.
But, they were also commanded to love even those who were outside of the covenant people of God…
Leviticus 19:34 (ESV)
You shall treat the stranger who sojourns with you as the native among you, and you shall love him as yourself, for you were strangers in the land of Egypt: I am the Lord your God.
The Old Testament book of Leviticus provides wisdom for us New Covenant members as well (as to how we are to consider the unbeliever in our midst) because…
2 Timothy 3:16-17 (ESV)
All Scripture is breathed out by God and profitable for teaching, for reproof, for correction, and for training in righteousness, that the man of God may be complete, equipped for every good work.
Here is explicit advice from Peter to the New Covenant people, which will help to give us (Christians) a picture of what love looks like…
1 Peter 2:10-17 (ESV)
Once you were not a people, but now you are God’s people; once you had not received mercy, but now you have received mercy. Beloved, I urge you as sojourners and exiles to abstain from the passions of the flesh, which wage war against your soul. Keep your conduct among the Gentiles honorable, so that when they speak against you as evildoers, they may see your good deeds and glorify God on the day of visitation. Be subject for the Lord’s sake to every human institution, whether it be to the emperor as supreme, or to governors as sent by him to punish those who do evil and to praise those who do good. For this is the will of God, that by doing good you should put to silence the ignorance of foolish people. Live as people who are free, not using your freedom as a cover-up for evil, but living as servants of God. Honor everyone. Love the brotherhood. Fear God. Honor the emperor.
And… Godspeed, to the brethren!