In vv. 16-22 the history of Joseph is poetically and summarily treated, as a link in the chain of providences which brought about the fulfilment of the Covenant. Possibly the singer is thinking about a captive Israel in the present, while speaking about a captive Joseph in the past. In God's dealings humiliation and affliction are often, he thinks, the precursors of glory and triumph. Calamities prepare the way for prosperity. So it was in that old time; and so it is still. In this _résumé_ of the history of Joseph, the points signalised are God's direct agency in the whole--the errand on which Joseph was sent ("before them") as a forerunner to "prepare a place for them," the severity of his sufferings, the trial of his faith by the contrast which his condition presented to what God had promised, and his final exaltation. The description of Joseph's imprisonment adds some dark touches to the account in Genesis, whether these are due to poetic idealising or to tradition. In ver. 18_b_ some would translate "Iron came over his soul." So Delitzsch, following the Vulgate ("Ferrum pertransiit animam ejus"), and the picturesque Prayer-Book Version, "The iron entered into his soul." But the original is against this, as the word for _iron_ is masculine and the verb is feminine, agreeing with the feminine noun _soul_. The clause is simply a parallel to the preceding. "His soul" is best taken as a mere periphrasis for _he_, though it may be used emphatically to suggest that "his soul entered, whole and entire, in its resolve to obey God, into the cruel torture" (Kay). The meaning is conveyed by the free rendering above.
Ver. 19 is also ambiguous, from the uncertainty as to whose word is intended in _a_. It may be either God's or Joseph's. The latter is the more probable, as there appears to be an intentional contrast between "His word" in _a_, and "the promise of Jehovah" in _b_. If this explanation is adopted, a choice is still possible between Joseph's interpretation of his fellow-prisoners' dreams, the fulfilment of which led to his liberation, and his earlier word recounting his own dreams, which led to his being sold by his brethren. In any case, the thought of the verse is a great and ever true one, that God's promise, while it remains unfulfilled, and seems contradicted by present facts, serves as a test of the genuineness and firmness of a man's reliance on Him and it. That promise is by the psalmist almost personified, as putting Joseph to the test. Such testing is the deepest meaning of all afflictions. Fire will burn off a thin plating of silver from a copper coin and reveal the base metal beneath, but it will only brighten into a glow the one which is all silver.
There is a ring of triumph in the singer's voice as he tells of the honour and power heaped on the captive, and of how the king of many nations "sent," as the mightier King in heaven had done (vv. 20 and 17), and not only liberated but exalted him, giving him, whose soul had been bound in fetters, power to "bind princes according to his soul," and to instruct and command the elders of Egypt.
Vv. 23-27 carry on the story to the next step in the evolution of God's purposes. The long years of the sojourn in Egypt are summarily dealt with, as they are in the narrative in Genesis and Exodus, and the salient points of its close alone are touched--the numerical growth of the people, the consequent hostility of the Egyptians, and the mission of Moses and Aaron. The direct ascription to God of all the incidents mentioned is to be noted. The psalmist sees only one hand moving, and has no hesitation in tracing to God the turning of the Egyptians' hearts to hatred. Many commentators, both old and new, try to weaken the expression, by the explanation that the hatred was "indirectly the work of God, inasmuch as He lent increasing might to the people" (Delitzsch). But the psalmist means much more than this, just as Exodus does in attributing the hardening of Pharaoh's heart to God.