Strengthen (4599) (sthenóō from sthénos = strength) denotes the idea of God giving them strength to bear all their sufferings without wavering in their faith. It means to cause someone to be or to become more able or capable, with the implication of a contrast with weakness. This verb is found only in this verse in the NT. Peter says that the God of grace promises to Himself provide the strength needed to resist the devil, holding one's ground when he roars. Barclay says that Through suffering God will strengthen a man. The Greek is sthenóō, which means to fill with strength. Here is the same sense again. A life with no effort and no discipline almost inevitably becomes a flabby life. No one really knows what his faith means to him until it has been tried in the furnace of affliction. There is something doubly precious about a faith which has come victoriously through pain and sorrow and disappointment. The wind will extinguish a weak flame; but it will fan a strong flame into a still greater blaze. So it is with faith." (The Daily Study Bible) Commenting on sthenóō MacDonald writes that Persecution is intended by Satan to weaken and wear out believers, but it has the opposite effect. It strengthens them to endure. (Believer's Bible Commentary) Wiersbe says Peter refers to - God’s strength given to us to meet the demands of life. What good is it to stand on a firm foundation if we do not have power to act?...Strengthen means just that: God’s strength given to us to meet the demands of life. What good is it to stand on a firm foundation if we do not have power to act?" (Bolding added) (Wiersbe, W: Bible Exposition Commentary. 1989. Victor) Goins writes that this word is literally, we will be "filled with bodily strength." It's like bodily discipline through exercise which toughens up a flabby body, replacing fat with muscle. That's what God's doing to us through suffering. In our suffering we have the perspective of the Olympic athlete who is in training because he is shooting for the gold medal. He knows that's where he's headed, he knows that's the purpose in all of his pain and difficulty. ESTABLISH: autos...themeliosei (3SFAI): Note that some manuscripts omit this verb, which accounts for its omission in the ASV, although the majority of texts support it as in the original text. "Copy and paste the address below into your web browser in order to go to the original page which will allow you to access live links related to the material on this page - these links include Scriptures (which can be read in context), Scripture pop-ups on mouse over, and a variety of related resources such as Bible dictionary articles, commentaries, sermon notes and theological journal articles related to the topic under discussion." http://www.preceptaustin.org/1_peter_510-14.htm#Strengthen%20(4599)%20sthenoo