For no Christian is to think that when he fares ill God has forgotten him or is angry with him. For this is God’s way and manner, that like a good father He is always after His children with the rod, in order that through such correction they may be admonished and kept from sin; since they would otherwise, if there were no correction, feel secure and continue in sin. Therefore a Christian is not only not to be offended at his misery, but to derive the assurance therefrom that God loves him, thinks of him and seeks what is best for him. As also the wise man says: “If a father really loves his son, he corrects him.”
Hence it is a great mistake if you judge of God’s goodness and grace by your temporal condition. It is true, indeed, money and goods, a healthy body, and the like, are gifts and blessings of God, but such a blessing as shall not endure forever. For at last everything must be left behind at any rate. Besides, to this blessing the evil attaches itself, that if one does not especially abide in the fear of God and pay strict attention to the Word, it gives rise to much sin on account of our sinful nature. (Luther’s House Postil, Sermon for the First Sunday after Trinity, Volume 3, p. 647)