Dynamis is the Greek word for power — behind our words dynamic and dynamite. In the New Testament it names God's mighty power at work: in the miracles of Jesus, in the raising of the dead, and in the gospel itself, which Paul calls the dynamis of God unto salvation. It is power that accomplishes what human strength never could.
Crucially, this power is promised to ordinary believers. Jesus told his disciples they would receive dynamis when the Holy Spirit came upon them — power to witness, to endure, to live changed lives. And Paul learned that this power is made perfect in weakness: dynamis is not our own capability, but God's strength poured into our inadequacy.
Dynamis in Scripture
But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth.