“When peace comes, we will perhaps in time be able to forgive the Arabs for killing our sons, but it will be harder for us to forgive them for having forced us to kill their sons.”

Riyadh-as-Saliheen by Imam Al-Nawawi, volume 3, hadith number 442
Sunni Hadith

Source: The Picture of Dorian Gray

On the September 11, 2001 attacks, in CNN broadcast of an interview http://edition.cnn.com/interactive/world/0302/timeline.bin.laden.audio/content.6.html that Al-Jazeera conducted in October 2001 (31 January 2002).
2000s, 2002

Source: Fences

Source: Father and Child Reunion (2001), p. 98.

1950s, Loving Your Enemies (Christmas 1957)
Context: Forgiveness does not mean ignoring what has been done or putting a false label on an evil act. It means, rather, that the evil act no longer remains as a barrier to the relationship. Forgiveness is a catalyst creating the atmosphere necessary for a fresh start and a new beginning. It is the lifting of a burden or the canceling of a debt. The words "I will forgive you, but never forget what you have done" never explain the real nature of forgiveness. Certainly one can never forget, if that means erasing totally for his mind. But when we forgive, we forget in the sense that the evil deed is no longer a mental block impeding a new relationship. Likewise, we can never say, "I will forgive you, but I won't have anything further to do with you." Forgiveness means reconciliation, a coming together again. Without this, no man can ever love his enemies. The degree to which we are able to forgive determines the degree to which we are able to love our enemies.

Source: Love Is Letting Go of Fear

The Idiot (1868–9)

After an assassin had tried to kill him, he ordered his soldiers not to kill the assassin, 1581., as quoted in William the Silent (1897) by Frederic Harrison, p. 223