A tract written by the late Arthur W. Pink

"Why should I, who am by nature no different from the careless and godless throngs all around, have been chosen in Christ before the foundation of the world and now blest with all spiritual blessings in the heavenlies in Him?
Why was I, that once was an alien and a rebel, signaled out for such wondrous favors? Ah, that is something I cannot fathom. Such grace, such love, "passes knowledge." But if my mind is unable to discern a reason, my heart can express its gratitude in praise and adoration. But not only should I be grateful to God for His grace toward me in the past, His present dealings will fill me with thanksgivings.

What is the force of that word "Rejoice in the Lord alway" (Phil. 4:4)?

Mark it is not "Rejoice in the Savior", but we are to "Rejoice in the Lord", as "Lord", As THE MASTER OF EVERY CIRCUMSTANCE.

Need we remind the reader that when the apostle penned these words he was himself a prisoner in the hands of the Roman government.
A long course of affliction and suffering lay behind him. Perils on land and perils on sea, hunger and thirst, scourging and stoning, had all been experienced. He had been persecuted by those within the church as well as by those without: the very ones who ought to have stood by him had forsaken him.
And still he writes, "Rejoice in the Lord always" What was the secret of his peace and happiness? Ah! had not this same apostle written, "And we know that all things work together for good to them that love God, to them who are the called according to His purpose"all things are under the control of and are being regulated by the Supreme Sovereign, (Rom. 8:28)? But how did he, and how do we, "know", that all things work together for good? The answer is, Because and because He has naught but thoughts of love toward His own, then "all things are so ordered by Him that they are MADE TO MINISTER TO OUR ULTIMATE GOOD.
 It is for this cause we are to give "thanks always for all things unto God and the Father in the name of our Lord Jesus Christ" (Eph. 5:20).
Yes, give thanks for "all things" for, as it has been well said "Our disappointments are but His appointments." To the one who delights in the sovereignty of God the clouds not only have a 'silver lining' but they are silver all through, the darkness only serving to offset the light!"