Acts 7:18

Which knew not Joseph - That is, did not approve of him, of his mode of governing the kingdom, nor of his people, nor of his God. See the note on Exodus 1:8.

Till another king arose - This is quoted from Exodus 1:8. What was the "name" of this king is not certainly known. The "common" name of all the kings of Egypt was "Pharaoh," as "Caesar" became the common name of the emperors of Rome after the time of Julius Caesar: thus we say, Augustus Caesar, Tiberius Caesar, etc. It has commonly been supposed to have been the celebrated Rameses, the sixth king of the eighteenth dynasty, and the event is supposed to have occurred about 1559 years before the Christian era. M. Champollion supposes that his name was Mandonei, whose reign commenced in 1585 b.c., and ended 1565 years before Christ (Essay on the Hieroglyphic System, p. 94, 95). Sir Jas. G. Wilkinson supposes that it was Amosis, or Ames, the "first" king of the eighteenth dynasty (Manners and Customs of the Ancient Egyptians, vol. 1, pp. 42, 2nd ed.). "The present knowledge of Egyptian history is too imperfect to enable us to determine this point" (Prof. Hackett).

Which knew not Joseph - It can hardly be supposed that he would be ignorant of the name and deeds of Joseph; and this expression, therefore, probably means that he did not favour the designs of Joseph; he did not remember the benefits which he had conferred on the nation; or furnish the patronage for the kindred of Joseph which had been secured for them by Joseph under a former reign. National ingratitude has not been uncommon in the world, and a change of dynasty has often obliterated all memory of former obligations and compacts.

7:18 Another king - Probably of another family.