Stephen's dying words, as he is being pummeled to death with stones by the Jewish leaders and officials: "Lord, don't hold this sin against them!" (Acts 7.60).
I am always impressed by Stephen's power to forgive here, but really his own forgiveness is only secondary. What is truly impressive is that he calls for God to forgive as well, not to hold this instance of murder -- perhaps the most heinous of all crimes -- against his enemies.
John Calvin, in his commentary on this verse, appreciates the power of Stephen's example in motivating us to forgive:
This is the other part of his prayer, wherein he joineth the love of men with faith in Christ; and surely if we desire to be gathered to Christ for our salvation, we must put on this affection. Whereas Stephen prayeth for his enemies, and those most deadly, and even in the very instant when their cruelty might provoke him unto desire of revenge, he declareth sufficiently what affection he beareth toward all other men.
And we know that we are all commanded to do the same which Stephen did; but because there is nothing more hard than so to forgive injuries, that we will wish well to those who would have us undone (Matth. v. 43, 44;) therefore we must always set Stephen before our eyes for an example.
There is an interesting consequence to this. Stephen forgives and furthermore calls God to forgive, not insofar as he was a softy, a bleeding-heart liberal who couldn't stand the strictness of God's retributive justice; rather it is because he was "full of the Holy Spirit" (6.5, 7.55). The Holy Spirit in Stephen moves him not only to forgive, but to plead with the Father that he forgive as well.
This tells me that God is not ultimately interested in judgment and punishment. What he wants is forgiveness, reconciliation, and he moves us to pray for these things, even as we are being murdered. Like Calvin said, we are called to forgive and to plead for forgiveness of our enemies with the Father as well. The Holy Spirit, the third person of the Holy Trinity, inspires us to embody the Son's example (cf. Luke 23.34) and pray to the Father that sins be forgiven, and that fellowship be restored. The goal of the Holy Trinity therefore is healing, reconciliation, and restoration. And I say that if there must be punishment, it is only ever ordered to this end, not for its own sake.