The website Weapon of Musical Defense quotes your book Churchill by Himself and records: “After 9-11 we were horrified at the hate & exhortations to violence we read in the Koran so we began learning more about what Winston Churchill called ‘the religion of blood and war.'” Did Churchill refer to Islam in those words? —I.L.
Yes, in his first book, The Story of the Malakand Field Force (London: Longmans Green, 1898). Quoting from the new edition (London: Leo Cooper, 1991), page 27:
But the Mahommedan religion increases, instead of lessening, the fury of intolerance. It was originally propagated by the sword, and ever since its votaries have been subject, above the people of all other creeds, to this form of madness. In a moment the fruits of patient toil, the prospects of material prosperity, the fear of death itself, are flung aside. The more emotional Pathans are powerless to resist. All rational considerations are forgotten. Seizing their weapons, they become Ghazis—as dangerous and as sensible as mad dogs: fit only to be treated as such. While the more generous spirits among the tribesmen become convulsed in an ecstasy of religious bloodthirstiness, poorer and more material souls derive additional impulses from the influence of others, the hopes of plunder and the joy of fighting. Thus whole nations are roused to arms. Thus the Turks repel their enemies, the Arabs of the Soudan break the British squares, and the rising on the Indian frontier spreads far and wide. In each case civilisation is confronted with militant Mahommedanism. The forces of progress clash with those of reaction. The religion of blood and war is face to face with that of peace. Luckily the religion of peace is usually the better armed.
It would be inappropriate to quote these words out of context with respect to modern situations. Churchill was, remember, confronting Muslim warriors at the reaches of the British Empire over 100 years ago; his broad reflections are however interesting.