Though these viewpoints appear contradictory, they really are not. Only a Christian disciplined in the Word of God can rest in the Lord. Yes, we can cease our striving and learn to relax in the confidence that God is equal to every situation. But a lazy, undisciplined Christian cannot do this; he falls apart at the seems when tragedy strikes. The believer who is like a tree planted by rivers of water is the one who meditates on the Law of God every free moment; his thoughts turn to the Word of God like a magnet."
Isaiah 26:3-4 "Thou wilt keep him in perfect peace, whose mind is stayed on thee: because he trusteth in thee. Trust ye in the LORD for ever: for in the LORD JEHOVAH is everlasting strength."
*excerpt from Winning the Inner War by Erwin W. Lutzer