I recently read Anxious for Nothing by John MacArthur, a book I would highly recommend to you. Here are 25 wonderful quotes from the book:

• Jesus said three times, “Do not be anxious” (see Matt. 6:25, 31, 34). Paul later reiterated, “Be anxious for nothing” (Phil. 4:6). Worry at any time is a sin because it violates the clear biblical command.
• We allow our daily concerns to turn into worry and therefore sin when our thoughts become focused on changing the future instead of doing our best to handle our present circumstances. Such thoughts are unproductive. They end up controlling us—though it should be the other way around—and cause us to neglect other responsibilities and relationships.
• Jesus gave us, His children, three reasons for not worrying about this life: It is unnecessary because of our Father, it is uncharacteristic because of our faith, and it is unwise because of our future.
• Christians who worry believe God can redeem them, break the shackles of Satan, take them from hell to heaven, put them into His kingdom, and give them eternal life; but they just don’t think He can get them through the next couple of days.
• When you or I worry, we are choosing to be mastered by our circumstances instead of by the truth of God.
• Lack of joy is a sin for the child of God.
• Prayer is our chief means of avoiding anxiety.
• Being thankful will release you from fear and worry. It is a tangible demonstration of trusting your situation to God’s sovereign control.
• The real challenge of Christian living is not to eliminate every uncomfortable circumstance from our lives, but to trust our sovereign, wise, good, and powerful God in the midst of every situation.
• Only from humility comes the ability to truly hand over all our cares to God.
• Spiritual maturity begins with these fundamentals: an attitude of humility toward God and others and trust in God’s care.
• Another weight or sin that “so easily entangles us” is doubt.
• Every time we sin, it’s because we believe Satan instead of God.
• Anxiety cannot survive in an environment of praise to God. If you have a problem facing you that you don’t know how to solve, remember to praise God.
• It’s exciting to know you can’t ever get yourself into a situation that God can’t remove you from if He so chooses. Let that truth help melt away any anxieties you have about a situation you currently dread.
• Pride and anxiety focus on self, whereas humility focuses on others.
• The church does well as a whole when the shepherds and the sheep bond together to correct the wayward, encourage the worried, hold up the weak, be patient with the wearisome, and repay the wicked with love. That is the bigger picture on attacking anxiety.
• There’s no greater gift for the anxious than God’s peace. It is not subject to circumstances.
• God’s grace saves us, helps us cope with our anxieties, equips us for service, and enables us to grow spiritually and to be rich in God. Like God’s peace, it is always available, and there is no limit to it.
• It is a sin to complain against God, and we must see our complaints as such.
• Complaining is the symptom of a deep-seated spiritual problem—a failure to trust God and submit to His will.
• Two roadblocks to contentment are grumbling and disputing.
• The quality of your life is the platform of your personal testimony. A murmuring, discontent, grumbling, griping, and complaining Christian is never going to have a positive influence on others.
• The Bible speaks of contentment not only as a virtue but also as a command.
• The example of Paul’s life throughout the New Testament is this: Work as hard as you can and be content that God is in control of the results.