This first paper in a series exploring young-Earth creationism (YEC) examines its theological foundations and Biblical rationale, laying the groundwork for a broader, interdisciplinary analysis. Grounded in a literal interpretation of Genesis, it focuses on key scriptural evidence, including genealogies and Earth's chronology, that support an Earth age of approximately 6,000 years. This work also addresses theological challenges posed by old-Earth interpretations and highlights their implications for fundamental doctrines, such as the coherence of Christ's redemptive work. By reaffirming the authority of Scripture, this study establishes the Biblical cornerstone for subsequent explorations into scientific and philosophical dimensions of YEC.