In 1866 Alfred Nobel invented an explosive made of nitroglycerin absorbed in a porous material. It was by far the most powerful explosive that had so far been invented.
When Nobel and his friends saw what his invention could do, and had to decide on a name, they sought for the strongest possible word for power — in any language. The word they finally chose was the Greek word dunamis, from which our word dynamite is derived.
This word, in Greek also the strongest word for power, is used again and again in the New Testament and is generally translated simply “power”.
When our Lord wrought miracles, for example, St. Luke testifies that “the POWER [dunamis] of the Lord was present to heal” (Luke 5:17). In promising His apostles that they too would work miracles, He said: “Ye [shall] be endued with POWER [dunamis] from on high” (Luke 24:49).
When the Sadducees questioned the resurrection, Jesus answered: “Ye do err, not knowing the Scriptures, nor the POWER [dunamis] of God” (Matt. 22:29), and St. Paul declares that Christ was “declared to be the Son of God with POWER [dunamis]…by the resurrection from the dead” (Rom. 1:4).
Using this same word, Paul, by inspiration, declares that “the gospel of Christ…is THE POWER OF GOD UNTO SALVATION, to every one that believeth…” (Rom. 1:16). This is because, according to this gospel, or good news, “CHRIST DIED FOR OUR SINS”, and “THE PREACHING OF THE CROSS”, he says, is to believers “THE POWER OF GOD” (I Cor. 1:18).
But not only are believers saved by the power of God; they are “KEPT BY THE POWER OF GOD” (I Pet. 1:5). Indeed, the adjective of this same word “dunamis” is used in Hebrews 7:25, where we read that the Lord Jesus Christ is “ABLE…TO SAVE…TO THE UTTERMOST [THOSE] THAT COME UNTO GOD BY HIM”. Thus the Bible uses the very strongest word for power to show how secure is the salvation of those who trust in Christ. source