Matthew Henry Commentary Exodus 1:1-7

"Now these are the names of the sons of Israel, who came into Egypt (every man and his household came with Jacob): Reuben, Simeon, Levi, and Judah, Issachar, Zebulun, and Benjamin, Dan and Naphtali, Gad and Asher. And all the souls that came out of the loins of Jacob were seventy souls: and Joseph was in Egypt already. And Joseph died, and all his brethren, and all that generation. And the children of Israel were fruitful, and increased abundantly, and multiplied, and waxed exceeding mighty; and the land was filled with them." — Exodus 1:1-7 (ASV)

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 to the fathers. Though the performance of God's promises is sometimes slow, it is always sure.