John Owen scholar Crawford Gribben recounts Owen’s change in sentiment.
[I]n August 1649 [Cromwell] achieved, for the first time in hundreds of years of English intervention, the entire subjugation of Ireland. His goal was a massive extension of English power and Protestant religion. Cromwell’s military administrators pursued the pacification of Ireland with ruthless efficiency. Before their departure from England, his soldiers had been encouraged by the preaching of a young puritan to avenge the “blood of almost-expiring Ireland” – to avenge the deaths of Ulster Protestants that had occurred during the rising of 1641. And many soldiers took this encouragement to heart…
Owen’s experience of the conflict forced him to reconsider the language with which he had encouraged the campaign. His question centred on how best to represent the fact that “God did not send his Son into the world to condemn the world, but in order that the world might be saved through him” (John 3:17). So, he wondered, in an address to Westminster MPs, “How is it that Jesus Christ is in Ireland only as a lion staining all his garments with the blood of his enemies, and none to hold him out as a lamb sprinkled with his own blood to his friends?”
Owen’s answer to that question changed his politics. The invasion of Ireland had not really advanced “the sovereignty and interest of England,” he realised. “I could heartily rejoice, that, innocent blood being expiated, the Irish might enjoy Ireland so long as the moon endureth,” if “Jesus Christ might possess the Irish.” Owen would become a key theorist of religious toleration – and his theological convictions were formed during the chaos and trauma of the Cromwellian invasion of Ireland.