Exodus 1:1 These are the names of the sons of Israel who came to Egypt with Jacob, each with his household: Reuben, Simeon, Levi, and Judah, Issachar, Zebulun, and Benjamin, Dan and Naphtali, Gad and Asher. All the descendants of Jacob were seventy persons; Joseph was already in Egypt. Then Joseph died, and all his brothers and all that generation. But the people of Israel were fruitful and increased greatly; they multiplied and grew exceedingly strong, so that the land was filled with them.
From the call of Abraham, when God first told him he would make him a great nation, to the deliverance of his seed out of Egypt, were four hundred and thirty years; during the first two hundred and fifteen of which they were increased to seventy, but in the latter half, those seventy multiplied to six hundred thousand fighting men.(Benson)
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.(Henry)
The first verses of Exodus reach back some 430 years. The story of the Exodus begins where the story Genesis ends: a large family with a crucial place in God’s plan of the ages and their migration to Egypt. Joseph was the remarkable great-grandson of Abraham who saved Egypt – and the world – from terrible famine because he listened to God’s voice speaking through Pharaoh’s dream. Because of his wisdom and administration, he was lifted to high and honored office in Egypt. Yet eventually, Joseph died and the status his family enjoyed died with him. (Guzik)
The promise given to Abraham concerning a great nation coming from his family was God’s plan and promise. We look at the time from promise to Abraham until Joseph and there are 70 up till then. In three plus generations the family grew to 70 and were put in a place of protection and blessings in Egypt. These blessing continued for many years until the heart of the Egyptian Pharaoh at that time became hard against them. This time laps (~430 years) brings us to the Exodus. God’s chosen are now going to start their journey to the promised land that was proclaimed to Abraham.
Never let circumstances and time give you reason to doubt the promises of God. He is God and all of His plans and purposes will come to be in His perfect timing.