'Mighty' in the Bible

and have realized how good the word of God is and how mighty are the powers of the coming Age, and then fell away--

He added an oath, in order that, through two unchangeable things, in which it is impossible for Him to prove false, we may possess mighty encouragement--we who, for safety, have hastened to lay hold of the hope set before us.

deprived fire of its power, escaped being killed by the sword, out of weakness were made strong, became mighty in war, put to flight foreign armies.