The Greek adverb sēmeron (σήμερον) means today or on this very day. It appears about 41 times in the New Testament and is often used with theological weight to emphasize present fulfillment, immediate opportunity, or urgency. It corresponds closely to the Hebrew yom used with demonstrative force.
Sēmeron carries extraordinary theological freight in the New Testament. In Luke 4:21, Jesus reads from Isaiah 61 and declares, 'Today this scripture is fulfilled in your hearing' — sēmeron is the word that marks the arrival of the messianic age. In Luke 2:11, the angel announces: 'Today in the town of David a Savior has been born to you.' The word 'today' in these passages is not merely temporal but eschatological — it signals the inbreaking of God's kingdom. Hebrews 3:7–13 quotes Psalm 95 — 'Today, if you hear his voice, do not harden your hearts' — and applies it urgently to the present generation. Salvation is always a today matter.