Jesus said to love our enemies. We do that not because they deserve it, but as a response to the love of God already poured out on us in our own lives. We show our thanks for God's unconditional love in the way we live, by loving others unconditionally.
Based on Matthew 5:43-48:
Jesus said, ‘You have heard that it was said, “You shall love your neighbour and hate your enemy.” But I say to you, Love your enemies and pray for those who persecute you, so that you may be children of your Father in heaven; for he makes his sun rise on the evil and on the good, and sends rain on the righteous and on the unrighteous. For if you love those who love you, what reward do you have? Do not even the tax-collectors do the same? And if you greet only your brothers and sisters, what more are you doing than others? Do not even the Gentiles do the same? Be perfect, therefore, as your heavenly Father is perfect.
(New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org)