A very long extract, today, from Charles Spurgeon's The Treasury of David, in the additional notes from other authors on Psalm 105.
Verse 19. Until the time that his word came: the word of the LORD tried him.
This verse forms the key to the whole meaning of Joseph's mysterious trial, and at the same time illustrates a deep mystery in the spiritual life of man. By "the word of the Lord" that "tried him, "the psalmist evidently refers to the dreams of his future destiny which were sent to Joseph from God; and in saying that they tried him "until his word came, "he evidently means that his faith in those promises was tested by his long imprisonment, until the day of his deliverance dawned. Consider for a moment his position, and you will see the purpose of that trial. A youth educated amidst all the quiet simplicity of the early patriarchal life, he was haunted by dream visions of a mighty destiny. Those visions were mysteriously foretelling his government in Egypt, and the blessings which his wise and just rule would confer on the land; but while unable to comprehend them, he yet believed that they were voices of the future, and promises of God. But the quietude of that shepherd life was not the preparation for the fulfilment of his promised destiny. The education that would form the man who could withstand, firmly, the temptations of Egyptian life with its cities and civilization; the education that would form the ruler whose clear eye should judge between the good and the evil, and discern the course of safety in the hour of a nation's peril—all this was not to be gained under the shadow of his father's tent; it must come through trial, and through trial arising from the very promise of God in which he believed. Hence, a great and startling change crossed his life, that seemed to forbid the fulfilment of that dream promise, and tempted him to doubt its truth. Sold into Egypt as a slave, cast into prison through his fidelity to God, the word of the Lord most powerfully tried his soul. In the gloom of that imprisonment it was most hard to believe in God's faithfulness, when his affliction had risen from his obedience; and most hard to keep the promise clearly before him, when his mighty trouble would perpetually tempt him to regard it as an idle dream. But through the temptation, he gained the strong trust which the pomp and glory of the Egyptian court would have no power to destroy; and when the word of deliverance came, the man came forth, strong through trial, to fulfil his glorious destiny of ruling Egypt in the name of God, and securing for it the blessings of heaven. Thus his trial by the word of the Lord—his temptation to doubt its truth—was a divine discipline preparing him for the fulfilment of the promise. And looking at it in this aspect, this verse presents to us a deep spiritual truth: The promises of God try man, that through the trial he may be prepared for their fulfilment. Our subject then is this: The trial of man by the promises of God.
This verse suggests three great facts which exhibit the three aspects of that trial.
1. God's promises must try man. Every promise of the Lord is of necessity a trial. Now, this necessity arises from two sources; from man's secret unbelief, and from God's purposes of discipline.
(a) God's word must try man by revealing his secret unbelief. We never know our want of faith till some glorious promise rouses the soul into the attitude of belief; then the coldness and unfaithfulness of the heart are lighted up by that flash of belief, and the promise is a trial. Thus Paul with his profound insight into the facts of spiritual experience, says, "The word of the Lord is sharper than a two edged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and is a discerner of the thoughts and intents of the heart." In illustration of this we may observe that many promises of the Lord come to us, as they came to Joseph, like dream visions of the future. Visions come to the Christian soul, as grand and wonderful as those which came to the Hebrew youth of old; and they, too, are prophecies of what we are destined to be. There comes a time when the voice of God is more clearly heard, and the great inheritance revealed. No dream of the night—no spirit of the dead—has visited us; but like a spirit some truth of God has entered the soul's presence chamber and summoned it to noble aspiration and Christ like endeavour. Then the earnest of the future gleams on life's horizon. The Sabbath of eternity, with all its balm and music, seems near, and rapt with its glory, we are roused to all surrendering zeal. But I appeal to your experience whether it is not true that such revelations of the promise rapidly become times of trial. Then the mocking voice of unbelief tells us that aspiration is vain. The cold cross currents of indifference chill the fiery impulses of the heart. We are in prison like Joseph, by no material bars indeed, but by the invisible bonds of unbelief; and we find it most hard to keep the promise clear and bright, while tempted to believe that our aspirations were merely idle dreams. And there is that arousing, by the promise, of the soul's hidden unbelief, which makes every promise an inevitable trial.
(b) Again: God causes his promises to try nature that he may accomplish his own purposes of discipline. It is a law of our nature that no belief in any unseen thing can ever pass into the active form of strong endeavour to attain it, until we are tempted to disbelieve it. Thus the great idea of an undiscovered land across the wastes of the Atlantic smote the soul of Columbus; but it remained a dreamy faith until by opposition and ridicule he was tempted to regard it as a dream, and then it became heroic endeavour, and the land was found. Thus with all men of genius. They stand in the front of their age, with thoughts which the world cannot understand; but those thoughts are dreams until suffering and scorn try the men, and then they are awakened into effort to realise them. Hence God leads us into circumstances in which we are tempted to doubt his promises, that by temptation he may discipline faith into power. There is a wilderness of temptation in every life, and like Christ, we are often led into it, from the solemn hour when we heard the voice, "Thou art my son; " but like Christ, we come forth strong, through the long, silent wrestling with temptation, to do our Father's will.
2. God sends the Hour of Deliverance: "until the time that his word came." When the discipline was perfected, Joseph came forth ready for his mission. But our deliverance does not always come in this way. Take from the Bible histories the four great methods by which God sends deliverance. Sometimes by death. Thus with Elijah Weariness, loneliness, failure, had wrung from by death the strong man the cry, "Take away my life for I and not better than my fathers." The temptation was becoming too strong, and God sent deliverance in the chariot of fire. Sometimes by transforming the height of trial into the height of blessing. The three youths in Babylon had clenched their nerves for the climax of agony, when the fire became a Paradise. So, now, God makes the climax of trial the herald of spiritual blessedness. By suffering we are loosened from the bonds of time and sense; there is one near to us like the Son of God; and deliverance has come. Sometimes by the glance of love on the falling soul. Thus with Peter. The temptation was mastering him; one glance of that eye, and he went out weeping and delivered. Sometimes by continuing the trial, but increasing the power to endure it. Thus with Paul. After the vision of the third heaven came "the thorn in the flesh, "The temptation made him cry thrice to, God; the trial remained, but here was the deliverance" my grace is sufficient for thee." The suffering lost none of its pressure, but he learned to glory in infirmity; and then came his delivering hour.
3. God makes the Trial by Promise fulfil the Promise itself. In Joseph the temptation to doubt the word of God silently meetened [the word here appears at first to be a misprint, but in fact to make 'meet' is an older usage meaning to make suitable, to make fit, for the task] him for its fulfilment. So with us all. We hope not for an Egyptian kingdom, our dream vision is of a heavenly inheritance, and the palace of a heavenly King. But every temptation resisted, every mocking voice of doubt overcome, is an aid upwards and onwards. Trials, sufferings, struggles, are angels arraying the souls in the white robes of the heavenly world, and crowning it with the crown that fadeth not away. And when the end comes, then it will be seen that the long dreary endeavour to hold fast the dream promise—the firm resolute "no" to the temptation to disbelieve, are all more than recompensed with "the exceeding and eternal weight of glory."—Edward Zuscombe, in "Sermons preached at Kings Lynn." 1867.
I can't find any reference to Edward Zuscombe on the Net, so don't have any more information about this writer.