5 And all the souls that had come out of the loins of Jacob were seventy souls; and Joseph was in Egypt. 6 And Joseph died, and all his brethren, and all that generation. 7 And the children of Israel were fruitful, and swarmed and multiplied, and became exceeding strong; and the land was full of them.
Matthew Henry's Commentary on Exodus 1:5-7
Commentary on Exodus 1:1-7
(Read Exodus 1:1-7)
During more than 200 years, while Abraham, Isaac, and Jacob lived at liberty, the Hebrews increased slowly; only about seventy persons went down into Egypt. There, in about the same number of years, though under cruel bondage, they became a large nation. This wonderful increase was according to the promise long before made unto the fathers. Though the performance of God's promises is sometimes slow, it is always sure.