Loving your enemy is impossible in your own strength.
“I can do all things through Christ who gives me the strength.” Philippians 4:13
“But I tell you, do not resist an evil person. If anyone slaps you on the right cheek, turn to them the other cheek also.” Matthew 5:39
Loving your enemy is not random niceness, but radical obedience.
“On the contrary, if your enemy is hungry, feed him; if he is thirsty, give him something to drink. In doing this, you will heap burning coals on his head. Do not be overcome by evil, but overcome evil with good.” Romans 12:20-21