This dissertation argues that believer's baptism by immersion should precede communion as prerequisite to it, due to the explicit example of the New Testament, the assumed pattern that all believers are baptized, and a principle of analogy (continuity) from the necessity of circumcision before Passover. Chapter 1 surveys the ecclesiological landscape for answers to the question of who may partake in the Lord's Supper. Chapter 2 surveys four historical Baptist answers to the research question: (1) open communion; (2) close communion; (3) closed communion; and (4) ecumenical communion. The chapter highlights the strongest arguments for each view. Chapter 3 considers the relationship of circumcision to Passover within its covenantal context and argues that circumcision is consistently presented as prerequisite to Passover. Chapter 4 considers the relationship of baptism to the Lord's Supper in its covenantal context and highlights the assumption that believers are baptized. Chapter 4 also presents the exemplary nature of baptism occurring before the Lord's Supper in Acts 2:41-42 as the expected pattern for church practice until Christ returns. Chapter 5 considers the continuities and discontinuities between the signs of covenant entry (circumcision and baptism) and the signs of covenant participation (Passover and the Lord's Supper). Then, chapter 5 argues that circumcision functions analogously to baptism as a sign of covenant entry, with the former pointing forward typologically to circumcision of the heart in the new covenant and the latter pointing reflectively to the possession of a circumcised heart by the person being baptized. Thus, because circumcision was necessary to participate in Passover, the continuity between the two covenant signs suggests that baptism should precede the Lord's Supper in the new covenant. Chapter 6 summarizes the constructive argument of the dissertation and defends the close communion position against its rivals. Chapter 7 applies the thesis to the church by considering the relationship of baptism and the Lord's Supper, respectively, to the universal and local church. Then, chapter 7 applies close communion to the doctrine and practice of church membership and discipline. Chapter 8 concludes the dissertation.