Here is a list of various free resources on Christian nonviolence. It includes the church fathers, writings of pacifist leaning Christians throughout church history and websites. If you have any more resources to include, please let me know so I can expand the list!
Here is a document I’m working on to be an extensive source for studying Biblical nonviolence. It’s in its infancy right now, but I at least have some of the more prominent verses. I’d like to include some resources, deeper arguments, Biblical themes and responses to opposing views. If anyone has comments, suggestions or anything to add, again, please let me know so I can add it in.
As for reading the church fathers, both http://www.earlychristianwritings.com/ and http://www.newadvent.org/fathers/index.html are good. Here’s a short list of some of the relevant writings for each father. I’ll continue to add onto this.
Justin Martyr: First Apology 14-16, 39; Dialogue with Trypho 85, 96, 110
Irenaeus: Against Heresies Book 2 Chapter 32, Book 4 Chapter 34, Book 5 Chapter 24; Proof of Apostolic Preaching 61, 96
Clement of Alexandria: Exhortation to the Greeks 10; Paedagogus (The Instructor) Book I, Chapters 12,18; Book II Chapters 4, 18; Stromata (Miscellanies) Book II, Chapter 18
Tertullian: Apology 30, 31, 37, 42; Of Patience; An Answer to the Jews 3 ; The Shows 2, 16; On Idolatry 17-19; Against Marcion Book 3 Chapter 14, 21, 22, Book 4 Chapter 16, Book 5 Chapter 18; The Crown Everything, but especially 1-4, 11; To Scapula
Origen: On First Principles 4.18; Homilies on Joshua In particular 14, 15; Commentary on Matthew Commentary on 26:52; Against Celsus 1.1, 2.3, 3.7,3.8, 4.82, 4.83, 4.9, 5.33, 7.18-20, 7.22, 7.26, 7.58, 7.59. 7.61, 8.35, 8.55, 8.65-75; Commentary on John 20.290, 20.292
Cyprian: (http://www.ccel.org/ccel/schaff/anf05.iv.ii.html) To Demetrius 16, 17, 20; To Donatus 6, 7; Testimonies Against Jews Book III Chapters 8, 49, 106; On the Advantage of Patience, Epistle VIII To Martyrs and Confessors, On the Lapsed 10
Lactantius: (http://www.newadvent.org/fathers/0701.htm) The Divine Institutes 1.18, 3.18, 5.8, 5.10, 5.17-19, 5.23, 6.5 6.6, 6.9, 6.18, 6.20
Writings in Open Domain:
James Nayler: The Lamb’s War
John Cecil Cadoux: The Early Christian Attitude to War
Toyohiko Kagawa: Meditations on the Cross
The End of Just War: Why Christian Realism Require Nonviolence by Stanley Hauerwas
The Sacrifices of War and the Sacrifice of Christ by Stanley Hauerwas
Does ISIS Prove Nonviolence Wrong? by Ronald Snider
Creeds and Statements etc:
Schleitheim Confession Anabaptist, 1527
Elbing Catechism Mennonite, 1778