The Greek verb eneulogeo means to bless in or through — used to quote the Abrahamic promise that 'all nations will be blessed in/through you.' It appears in Acts 3:25 and Galatians 3:8 in direct citation of the Abrahamic covenant.
Eneulogeo is the verb of the Great Commission's foundation. When God promised Abraham 'all peoples on earth will be blessed through you' (Genesis 12:3), the LXX uses eneulogeo. Paul quotes this in Galatians 3:8 as the Scripture 'announcing the gospel in advance to Abraham' — the Abrahamic promise is itself gospel. All nations being blessed in Abraham is ultimately about all nations being blessed in Christ, Abraham's singular seed (Galatians 3:16). Peter uses the same quote in Acts 3:25 to argue that Jesus is the fulfillment of Israel's covenant: the blessing now flowing through the risen Christ to all who repent. The Great Commission is therefore not an addendum to the story — it is the fulfillment of the oldest promise in Scripture.