"When a man has that confident inner assurance that God’s will for his life is the design of an infinite wisdom and love, it will be as necessary, while in the possession of this faith, to be thankful and pleased with everything that God chooses as it would be to wish his own happiness. For what more could be asked than that every circumstance of life be the choice of an infinite wisdom and love? Whenever a man allows himself to have anxieties, fears, or complaints, he must consider his behavior as either a denial of the wisdom of God or as a confession that he is out of His will. To be always in a thankful state of heart before God is not to be considered a high plane of spirituality but rather the normal attitude of one who believes that “all things work together for good to them that love God, who are the called according to His purpose” (Romans:8:28And we know that all things work together for good to them that love God, to them who are the called according to his purpose.
See All...). If one cannot thank and praise God as well in calamities and sufferings as in prosperity and happiness, how can such an attitude be called a real trust in God at all? For to thank God only for pleasant incidents in life is no more a proper act of piety than to believe only what can be verified with the senses would be an act of faith."
—From "The Power of the Spirit" by William Law, edited and updated by Dave Hunt