This paper investigates the ethical teachings of the Historical Jesus through the framework of Second Temple Jewish apocalypticism, arguing that his moral imperatives were fundamentally shaped by an expectation of imminent divine intervention. Analyzing Synoptic Gospel traditions, the Q source, and comparative Jewish apocalyptic texts (e.g., Daniel, 1 Enoch, Dead Sea Scrolls), the study demonstrates that Jesus’ radical ethics—including renunciation of wealth (Luke 12:33), nonviolent resistance (Matthew 5:44), and inclusivity of marginalized groups (Luke 15:1–2)— functioned as both preparation for and performative enactment of the “Kingdom of God.” Engaging scholarly debates between proponents of an apocalyptic Jesus (Schweitzer, 1906; Ehrman, 1999) and advocates of a wisdom-oriented Jesus (Borg, 1987; Crossan, 1991), the research employs historical-critical methods, including criteria of authenticity and social memory theory, to prioritize sayings such as Mark 1:15 and Matthew 25:31–46. Findings reveal that Jesus’ ethics were rooted in cosmic dualism, eschatological reversal, and urgency, reflecting Jewish apocalyptic motifs like divine judgment and resurrection. The study further examines how early Christian communities adapted these ethics amid delayed eschatological expectations, fostering practices such as communal resource-sharing (Acts 2:44–45) and martyrdom theology (Revelation 2:10). By bridging theological and socio-political analyses, the paper reaffirms Schweitzer’s “consistent eschatology” while integrating modern insights into Jesus’ subversion of Roman and Temple hierarchies. It concludes that apocalypticism was central to Jesus’ ethical vision, offering a transformative framework that sustained early Christian identity and remains relevant to contemporary discussions on social justice and ethical radicalism.