Sermon by Gurnall entitled - DON'T TRUST IN YOUR OWN STRENGTH -
http://www.ccel.org/ccel/gurnall/armour/files/armour.html
Is the Christian's strength in the LORD, and not in himself? Surely then, the person outside of Christ must be a poor, impotent creature,, helpless to do anything to effect his own salvation. If a living tree cannot grow without sap from the tap root, how can a rotten stump, which has no root, revive itself of it's own accord? In other words, if a Christian imbued with God's grace must continually rely on His strength, then surely the one outside of God's grace, dead in trespasses and sin, can never produce strength in himself. To be unregenerate is to be impotent. "When we were without strength, in due time Christ died for the ungodly ( Romans 5:6 ).
The philosophy of humanism has long been a suitor to man's pride. It boasts in his natural strength and wisdom, and woos him with promises of great accomplishments now, and heaven later. God Himself scattered such Babel-builders and proclaimed preeminence for eternity. Confounded forever be such sons of pride, who trust in power of nature as though man with his own brick and mortar of natural abilities were able to make a way to heaven! You who are yet in your natural state, would you become wise to salvation? Then first become fools in your own eyes. Renounce the carnal wisdom which cannot perceive spiritual things, and beg wisdom from God, who gives without rebuke (James 1:5).
Here is a word for Christians. Knowing your strength lies wholly in God and not in yourself, remain humble - even when God is blessing and using you most. Remember, when you have your best suit on, who made it and who paid for it!
God's favor is neither work in your hands nor the price of your own worth. How can you boast in what you did not buy? If you embezzle God's strength and credit it to your own account, He will soon call an audit and take back what was His all along.