John Calvin Commentary Hebrews 11:34

"quenched the power of fire, escaped the edge of the sword, from weakness were made strong, waxed mighty in war, turned to flight armies of aliens." — Hebrews 11:34 (ASV)

Out of weakness were made strong, etc. Chrysostom refers this to the restoration of the Jews from exile, in which they were like men without hope; I do not disapprove of its applications to Hezekiah. We might at the same time extend it wider, that the Lord, by his hand, raised on high his saints, whenever they were cast down; and brought help to their weakness, so as to endow them with full strength.