The idea and practice of a purge has become so tied up with political processes that it is worth recalling that it also has distinct theological resonances, indeed that it is highly translatable between theology and politics. The Apostle Paul writes in 1 Corinthians 5:7: ‘Purge [ekkatharate] the old yeast, so that you may be a new batch’, using the metaphor of yeast and bread for the Christian life. The ‘old yeast’ of malice and evil should be replaced with the new yeast of Christ, for it leavens the whole dough (1 Cor. 5:6). The verb, ekkathairo means cleansing, removing what is unclean. Crucially, the translation of the biblical passage in the Latin Vulgate is expurgate (expurgare), with a comparable sense (that at the same time opens up a slightly different semantic field) of cleansing, freeing or clearing away from unwanted matter, and then clearing oneself from blame. Purgare has a similar meaning, with the sense of cleansing from or ridding dirt and impurities.
For the early Christians, purging clearly related to body and soul of the believer. Christ was the physician who heals the soul, if not the body itself. The impurities that arose from sin or the activities of the devil included as much physical ailments, deformities, pain and illness, just as mental difficulties signalled an afflicted soul. Thus, the resurrected body would be one that was whole and vigorous, freed from the deleterious effects of sin and where an equally whole and clean soul would be at peace. And it was God who purged one of sin so as to be purified and restored to God. But one could also participate, through redemptive pain (like Christ), ascetic practice, fasting, chastity and self-deprivation.
Under the influence of Pseudo-Dionysius the Areopagite (of the late fifth and early sixth centuries CE), purging became crucial to the stages in the Christian life: purification, illumination and union. It applied to individual life, hierarchies of angels and the church itself (catechumens, baptised and monks). As the Latin and Greek traditions diverged, the theory and practice of purging took distinct paths in some respects (notably the Latin doctrine of purgatory) and overlapped, especially in terms of monasticism. Indeed, in Orthodox theology, monasticism became a core feature and the source of renewal.
Since I have been engaged for a while in a detailed study of Stalin, let me note that the official synodal Russian translation of 1 Cor. 5:7 uses ochistite (perfect of chistitʹ) – to clean, clear and purge – for the Greek ekkatharate. The noun, chistka would be the main term used by the Bolsheviks. I am not of course claiming a direct and conscious lineage from the biblical text of 1 Cor. 5:7, but rather a terminological, cultural if not theological framework within which the terminology of purge was translatable across theological and Marxist political usage. This was already the case with Lasalle’s famous slogan, cited often by Stalin and indeed Lenin: ‘the party become strong by purging itself [Partiia ukrepliaetsia tem, chto ochishchaet sebia]’.
In Stalin’s texts, a purge is a natural process of the Party. The term was applied to the regular screening of Party members, seeking to weed out the ‘hangers-on, nonparticipants, drunken officials, and people with false identification papers, as well as ideological “enemies” or “aliens”’. Already from early on, it was seen as a necessary and beneficent revolutionary process, ‘purging [ochishcheniia] the revolution of “unnecessary” elements’, one that would continue with the Party when in power. Over the following years, he came to depict purging in different ways, including the natural process of tidying up the party’s membership, of a ‘cleaning up’ (chistka) and ‘sifting’ or ‘filtering’ (filtrovki) the cadres of the Red Army so as to ensure reliable Bolsheviks at its core, of theoretical re-education of aforesaid members, of strengthening the Party through struggle and getting rid of unstable and unreliable elements, of ‘purging itself of dross’ (ochishchaet sebia ot skverny), of reminding members that the Party exists and of ensuring quality rather than quantity so as not to become a ‘colossus with feet of clay’.
On a more theological register, a purge reminds people that a master exists, the Party, which ‘can call them to account for all sins committed against it’. It is necessary that ‘this master [khoziainu] go through the Party ranks with a broom every now and again’.
 In 2 Timothy 2:21 the reflexive appears (ekkathare eauton), cleanse yourself, now by analogy with a utensil.
 Isabel Moreira, Heaven’s Purge: Purgatory in Late Antiquity (Oxford: Oxford University Press, 2010), pp. 63-6.
 The synodal translation was first published in full in 1878 under the direction of the Most Holy Synod, and would have been used by Stalin in his theological studies (1895-99).
 I. V. Stalin, “The Political Strategy and Tactics of the Russian Communists,” in Works, vol. 5, 63-89 (Moscow: Foreign Languages Publishing House, 1921 ), p. 73; I. V. Stalin, “O politicheskoĭ strategii i taktike russkikh kommunistov: Nabrosok plana broshiury,” in Sochineniia, vol. 5, 62-87 (Moscow: Gosudarstvennoe izdatel´stvo politicheskoi literatury, 1921 ), p. 72.
 John Arch Getty, Origins of the Great Purges: The Soviet Communist Party Reconsidered, 1933-1938 (Cambridge: Cambridge University Press, 1985), p. 38. Although Kharkhordin does not deal with Stalin in any extended way, his discussion of the theory and practice of purges in the strict sense has some useful insights, especially in terms of the need for unity and ‘fusion’ or ‘cohesion’ (spaika): Oleg Kharkhordin, The Collective and the Individual in Russia: A Study of Practices (Berkeley: University of California Press, 1999), pp. 133-42. It is important to note that trials, operations, arrests and terror were not designated purges. However, since scholarly usage has since included such matters under the label of ‘purge’, I do so here as well.
 I. V. Stalin, “The Land to the Peasants,” in Works, vol. 3, 36-38 (Moscow: Foreign Languages Publishing House, 1917 ), p. 38; I. V. Stalin, “Zemliu – krestʹianam,” in Sochineniia, vol. 3, 34-36 (Moscow: Gosudarstvennoe izdatel´stvo politicheskoi literatury, 1917 ), p. 36.
 I. V. Stalin, “Report to V.I. Lenin from the Eastern Front,” in Works, vol. 4, 190-93 (Moscow: Foreign Languages Publishing House, 1919 ), p. 190; I. V. Stalin, “Pisʹmo V.I. Leninu s Vostochnogo fronta, 5 ianvaria 1919 g.,” in Sochineniia, vol. 4, 186-89 (Moscow: Gosudarstvennoe izdatel´stvo politicheskoi literatury, 1919 ), p. 186; Stalin, “Report to V.I. Lenin,” pp. 195, 197; Stalin, “Doklad V.I. Leninu,” pp. 191, 193; Stalin, “Report to Comrade Lenin by the Commission of the Party Central Committee and the Council of Defence on the Reasons for the Fall of Perm in December 1918,” pp. 211, 215, 230-1; Stalin, “Otchet Komissii TSK partii i Soveta Oborony tovarishchu Leninu o prichinakh padeniia Permi v dekabre 1918 goda,” pp. 204, 208, 222-3; Stalin, “Excerpt from a Speech on the Military Question Delivered at the Eighth Congress of the R. C. P. (B.), March 21, 1919.”; Stalin, “Iz rechi po voennomu voprosu na VIII s”ezde RKP(b), 21 marta 1919 g..”; Stalin, “The Political Strategy and Tactics of the Russian Communists,” p. 73; Stalin, “O politicheskoĭ strategii i taktike russkikh kommunistov: Nabrosok plana broshiury,” p. 72; Stalin, “The Immediate Tasks of Communism in Georgia and Transcaucasia: Report to a General Meeting of the Tiflis Organisation of the Communist Party of Georgia, July 6, 1921,” pp. 100-1; Stalin, “Ob ocherednykh zadachakh kommunizma v Gruzii i Zakavkazʹe: Doklad obshchemu sobraniiu tiflisskoĭ organizatsii kommunisticheskoĭ partii Gruzii, 6 iiulia 1921 g.,” pp. 98-9; I. V. Stalin, “Thirteenth Congress of the R. C. P. (B.), May 23-31, 1924,” in Works, vol. 6, 197-245 (Moscow: Foreign Languages Publishing House, 1924 ), pp. 239-40; I. V. Stalin, “XIII s”ezd RKP(b) 23–31 maia 1924 g.,” in Sochineniia, vol. 6, 191-233 (Moscow: Gosudarstvennoe izdatel´stvo politicheskoi literatury, 1924 ), pp. 227-9; I. V. Stalin, “Report on the Work of the Central Committee to the Eighteenth Congress of the C.P.S.U.(B.) (Delivered March 10, 1939),” in Works, vol. 14, 355-429 (London: Red Star Press, 1939 ), pp. 400-1; I. V. Stalin, “Otchetnyĭ doklad na XVIII s”ezde partii o rabote TSK VKP(b), 10 marta 1939 goda,” in Sochineniia, vol. 14, 290-341 (Moscow: Izdatelʹstvo “Pisatelʹ”, 1939 ), pp. 322-3.
 Stalin, “Thirteenth Congress of the R. C. P. (B.), May 23-31, 1924,” p. 240; Stalin, “XIII s”ezd RKP(b) 23–31 maia 1924 g.,” p. 229.