More Volf on non-retaliation and God's justice

How does one not retaliate in the middle of brutal violence? How does one embrace non-retalitation when we're talking about something like genocide rather than only an unkind word? Miroslav Volf, a witness to violence in the Balkans, argues that non-retaliation is only possible when we leave vengeance to God:

If God were not angry at injustice and deception and did not make a final end to violence - that God would not be worthy of worship...The only means of prohibiting all recourse to violence by ourselves is to insist that violence is legitimate only when it comes from God...My thesis that the practice of non-violence requires a belief in divine vengeance will be unpopular with many...in the West...[But] it takes the quiet of a suburban home for the birth of the thesis that human non-violence [results from the belief in] God's refusal to judge. In a sun-schorched land, soaked in the blood of the innocent, it will invariably die...[with] other pleasant captivities of the liberal mind. (Exclusion and Embrace)