A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
gen 45:1JOSEPH MAKING HIMSELF KNOWN. (Gen. 45:1-28)
Then Joseph could not refrain himself--The severity of the inflexible magistrate here gives way to the natural feelings of the man and the brother. However well he had disciplined his mind, he felt it impossible to resist the artless eloquence of Judah. He saw a satisfactory proof, in the return of all his brethren on such an occasion, that they were affectionately united to one another; he had heard enough to convince him that time, reflection, or grace had made a happy improvement on their characters; and he would probably have proceeded in a calm and leisurely manner to reveal himself as prudence might have dictated. But when he heard the heroic self-sacrifice of Judah [Gen 44:33] and realized all the affection of that proposal--a proposal for which he was totally unprepared--he was completely unmanned; he felt himself forced to bring this painful trial to an end.
he cried, Cause every man to go out from me--In ordering the departure of witnesses of this last scene, he acted as a warm-hearted and real friend to his brothers--his conduct was dictated by motives of the highest prudence--that of preventing their early iniquities from becoming known either to the members of his household, or among the people of Egypt.
gen 45:2he wept aloud--No doubt, from the fulness of highly excited feelings; but to indulge in vehement and long-continued transports of sobbing is the usual way in which the Orientals express their grief.
gen 45:3I am Joseph--or, "terrified at his presence." The emotions that now rose in his breast as well as that of his brethren--and chased each other in rapid succession--were many and violent. He was agitated by sympathy and joy; they were astonished, confounded, terrified; and betrayed their terror, by shrinking as far as they could from his presence. So "troubled" were they, that he had to repeat his announcement of himself; and what kind, affectionate terms he did use. He spoke of their having sold him--not to wound their feelings, but to convince them of his identity; and then, to reassure their minds, he traced the agency of an overruling Providence, in his exile and present honor [Gen 35:5-7]. Not that he wished them to roll the responsibility of their crime on God; no, his only object was to encourage their confidence and induce them to trust in the plans he had formed for the future comfort of their father and themselves.
gen 45:6and yet there are five years, in the which there shall neither be earing nor harvest--"Ear" is an old English word, meaning "to plough" (compare Sa1 8:12; Isa 30:24). This seems to confirm the view given (Gen 41:57) that the famine was caused by an extraordinary drought, which prevented the annual overflowing of the Nile; and of course made the land unfit to receive the seed of Egypt.
gen 45:14And he fell upon . . . Benjamin's neck--The sudden transition from a condemned criminal to a fondled brother, might have occasioned fainting or even death, had not his tumultuous feelings been relieved by a torrent of tears. But Joseph's attentions were not confined to Benjamin. He affectionately embraced every one of his brothers in succession; and by those actions, his forgiveness was demonstrated more fully than it could be by words.
gen 45:17Pharaoh said unto Joseph, Say unto thy brethren--As Joseph might have been prevented by delicacy, the king himself invited the patriarch and all his family to migrate into Egypt; and he made most liberal arrangements for their removal and their subsequent settlement. It displays the character of this Pharaoh to advantage, that he was so kind to the relatives of Joseph; but indeed the greatest liberality he could show could never recompense the services of so great a benefactor of his kingdom.
gen 45:21Joseph gave them wagons--which must have been novelties in Palestine; for wheeled carriages were almost unknown there.
gen 45:22changes of raiment--It was and is customary, with great men, to bestow on their friends dresses of distinction, and in places where they are of the same description and quality, the value of these presents consists in their number. The great number given to Benjamin bespoke the warmth of his brother's attachment to him; and Joseph felt, from the amiable temper they now all displayed, he might, with perfect safety, indulge this fond partiality for his mother's son.
gen 45:23to his father he sent--a supply of everything that could contribute to his support and comfort--the large and liberal scale on which that supply was given being intended, like the five messes of Benjamin, as a token of his filial love [see on Gen 43:34].
gen 45:24so he sent his brethren away--In dismissing them on their homeward journey, he gave them this particular admonition:
See that ye fall not out by the way--a caution that would be greatly needed; for not only during the journey would they be occupied in recalling the parts they had respectively acted in the events that led to Joseph's being sold into Egypt, but their wickedness would soon have to come to the knowledge of their venerable father.