Alma 34:18 - What is the meaning of the phrase "mighty to save"?

In Alma 34:18, we can see some of Christ's "mightiness" in His miracles: healing the sick, raising the dead, and forgiving repentant sinners. He has the power to save us all, but that grace depends on our willingness to turn to Him. Christ is our Savior and Redeemer, and without Him we would be unable to repent of our sins so that we could be worthy to live with Him again.