σήμερον (sēmeron)

The Greek word sēmeron simply means "today." It points to the current day, whether referring to the daylight hours or the twenty-four-hour period that has just passed. In the New Testament, it appears frequently in Luke and Acts, often marking specific moments where God’s action intersects with human history. For instance, Jesus declares that Scripture is fulfilled "this very day" in Nazareth (Luke 4:21), and a repentant thief asks to be remembered when Jesus enters his kingdom (Luke 23:43).

Its etymology suggests a compound of the demonstrative "this" and the word for "day," emphasizing immediacy. The term is often contrasted with "tomorrow" (aúrion), highlighting the uncertainty of the future against the reality of the present. In Hebrews 3:13 and 4:7, it functions as a noun meaning "today," urging readers to respond to God’s voice now rather than hardening their hearts for later.

Translators consistently render sēmeron as "today" or "this day." Its theological weight lies in its urgency. It is not merely a chronological marker but a call to present response. The word underscores that divine promises and judgments are active in the current moment, demanding attention rather than deferred action.