From en ("in") and kratos ("strength/power"), egkrateia literally means "in-strength" — the ability to hold oneself within proper boundaries, to exercise mastery over one's impulses, desires, and actions. It appears in the fruit of the Spirit (Galatians 5:23), in the list of virtues for elders (Titus 1:8), and in Peter's list of faith-growth qualities (2 Peter 1:6).
Egkrateia is not stoic willpower or self-earned virtue — it is Spirit-produced strength. The Spirit who raised Christ from the dead (Romans 8:11) is the same Spirit who produces egkrateia in believers. Paul used athletic imagery: "Every athlete exercises self-control in all things" (1 Corinthians 9:25). The goal is not a joyless existence but a life liberated from slavery to appetite and impulse — free to pursue what truly satisfies. Felix trembled when Paul reasoned about egkrateia (Acts 24:25) — a convicting word for any age of addiction and indulgence.