A historical study and analysis of the life of the first Muslim caliph and the expression of his role in the spread and strengthening of Islam. Our goal is to review and rewrite the history and character of the companions of the Messenger of God and to recognize their place in the history of Islam. In this program, we will deal with the life of Abu Bakr Siddiq in detail and with special detail and punctuation. At the beginning of his genealogy, we describe his family and titles, and describe a glimpse of his life and activities during the pre-Islamic period. In the following, we will deal with the life of Abu Bakr after the advent of Islam and explain his motivation and how he migrated to Medina with the Messenger of Islam. Then we examine his presence and role in the jihadi fields and enumerate his characteristics and virtues. Then, we recount the events after the death of the Prophet and the role of Abu Bakr in the incident of Saqifa, the appointment of the caliph of the Prophet and the dispatch of Osama's army. An analytical study of Abu Bakr's wars with apostates and the events of his caliphate is one of the topics that will be discussed below. The final chapter is dedicated to the death of Abu Bakr and how Umar came to the caliphate.