Source
When we are truly transformed by the love of God, we can sincerely love the hostile.
The Lord Jesus expressed it as follows to his disciples.
Luke 6: 31-35 King James Version (NIV)
31 And as you want men to do with you, you also do it with them. 32 Because if you love those who love you, what merit do you have? Because sinners also love those who love them. 33 And if you do good to those who do you good, what merit do you have? Because sinners do the same. 34 And if he lends to those he expects to receive, what merit does he have? Because sinners also lend to sinners, to receive the same. 35 Love therefore your enemies, and do good, and lend, expecting nothing from him; and it will be your great reward, and you will be children of the Most High; because he is kind to the ungrateful and the bad.
To love the ruthless is to renounce the selfish love of the world; It is about the love of Christ with people who apparently have no chance of offering any reward. Jesus asks us to love as He loved the last to arrive, the ugly, the poor or those who have no means to help us. This is possible only through a supernatural transformation that engenders in us an order of response different from that which human society accustoms. Just as the human mind distinguishes people from animals, Christian love must be dramatically different, so that it distinguishes the believer from the world around him.
It is to shed animal reactions that make us complain, attack or avenge ourselves. It must transcend human responses that await an earthly reward for a service rendered or for an act of kindness. Such love will be like a ray of light that will bring the world closer to ask what makes us radiate love amid hostile people. Stephen exemplifies this love (Acts 7: 59-60) and Saul (Acts 9: 5). Notice the "stings" of guilt that began to prick him, no doubt through Esteban's love. The perfection of God's love in us can win us a curious and attentive audience.