Shortly after the Islamic Revolution of Iran, Iraq initiated a war against the revolutionized country. Along with the professional but severely debilitated pre-revolutionary army, a second body of Iranian combatants found themselves fighting the Iraqi army: the Islamic Revolutionary Guard Corps (IRGC). The Corps was just a young revolutionary institution rooted in the religious-ideological groups that had played a significant role during the Revolution itself. Rigid structure, efficient planning and decision-making capability, trained staff, and formal processes of granting authority are known as essential characteristics of successful armed forces. Yet, clearly lacking such features, the IRGC got heavily involved in the war alongside a classical army and even achieved military successes in the second year of the war. How did this nonprofessional and disorganized military body survive the ultimate pressure of international combat and secure military achievements? What informally accepted principles filled the void of a classic military structure and training, and how? This paper examines about 80 wartime diaries and memoires written by the IRGC veterans of different ranks, in an attempt to disclose the internal flow of interactions, interpersonal relationships, and collective understandings that kept the nascent organization together and endowed it with military creativities of its own. Where there is no externally observable order, the personal narratives under study provide an insider’s view of the organization’s consolidation and everyday functioning in the first two years of war. Findings show that the Guards relied on two intertwined assets. On one hand, the large, all-volunteer rank and file’s religiously-inspired revolutionary fervor provided them with a strong sense of solidarity as well as a selfless readiness—know among them as “will to martyrdom”—to take extreme measures on the battlefield. On the other hand, commanders shared and understood this spirit, which allowed them not only to gain the soldiers’ deep trust, but also to adjust their institutionalization efforts so that this shared fervor was not “disenchanted” away. Hierarchy was kept at minimum in the spirit of brotherhood, self-identification with the Islamic Revolution and its underlying Shi’a culture was considered the highest merit, decision-making was religiously inspired, and Islamic rituals and ethics were deployed as organizing elements. In short, it was the rank and file’s Islamic-revolutionary spirit combined with the commanders’ attempt to preserve this spirit throughout institutionalization that allowed the Guards to operate quite successfully in the first two years of the war.