Jesus builds this section on a rhythm of matched refusals and one closing command. 27"Love your enemies, do good to those who hate you, bless those who curse you, pray for those who abuse you." Four verbs aimed at four kinds of hostile people, an enemy, a hater, a curser, an abuser. It names hostility and commands love straight into it.
Jewish teaching of the period already had something close in negative form: do not do to another what you would hate done to you. It was wise counsel and a boundary against cruelty. Jesus reshapes it: 31"As you wish that others would do to you, do so to them." The shift from a negative boundary to a positive command changes what the teaching requires. Not doing harm is a floor. Actively seeking someone's good, especially an enemy's, is something else, and it is what Jesus asks.
Three times he dismantles the ordinary ethic people practice without calling it virtue. 32"If you love those who love you, what benefit is that to you? For even sinners love those who love them." Loving people who love you back costs nothing and proves nothing. The same goes for doing good to those who do good to you, and for lending to people who will repay in full: 34"Even sinners lend to sinners, to get back the same amount." These ordinary reciprocities are self-interest wearing the costume of virtue, and none of them distinguishes a follower of his from anyone else.
Then the turn: 35"Love your enemies, and do good, and lend, expecting nothing in return." This is love with the payment structure removed, given without confidence or even expectation that it will be returned. The reason Jesus gives is theological: 35"You will be sons of the Most High, for he is kind to the ungrateful and the evil." It is family resemblance. God is kind to people who never thank him and never deserve it, sending, as Jesus says elsewhere, sun and rain on the just and the unjust. A child who loves the way this Father loves shows, in miniature, whose family he belongs to.
The passage closes on a sentence that reframes everything before it: be merciful, even as your Father is merciful. Matthew records the same saying with the word perfect (Matthew 5:48), and Luke chooses the word mercy, which names what perfection looks like toward an enemy. The standard is a character to reflect. Mercy toward an enemy is evidence of whose child you are. Luke shows the command lived out. Jesus heals the ear of the man who comes to arrest him (Luke 22:50-51) and prays from the cross, "Father, forgive them, for they know not what they do" (Luke 23:34), and in Luke's second volume Stephen dies echoing that prayer (Acts 7:60). The command was never only a sermon.
Ask whose name comes to mind at the phrase "expecting nothing in return," and start there.
Prayer
Father, you are kind to the ungrateful and the evil, and you ask your children to be kind the same way. Forgive us for the mercy we have rationed, given only where we expected something back. Teach us to love our enemies as you loved us while we were still your enemies, expecting nothing in return, so that whoever watches us might see, even faintly, a family resemblance to you. In Jesus' name, amen.