These few slides are an expansion of the prophecy given to Abraham, that his seed should sojourn in a land that was not theirs for 400 years. Later in Exodus, and also in Galatians, the period from the giving of the promise to Abraham (that his seed should inherit the land), unto the giving of the Law (on Mt. Sinai) is stated as being 430 years. These slides reconcile those two dates, and fill in the details surrounding those prophecies.
The reason for putting them in here, under The Desire of Ages, chapter 3, is that the prophecy is mentioned in the following paragraph from that chapter:
The Desire of Ages, p. 32
But like the stars in the vast circuit of their appointed path, God’s purposes know no haste and no delay. Through the symbols of the great darkness and the smoking furnace, God had revealed to Abraham the bondage of Israel in Egypt, and had declared that the time of their sojourning should be four hundred years. “Afterward,” He said, “shall they come out with great substance.” Genesis 15:14. Against that word, all the power of Pharaoh’s proud empire battled in vain. On “the self-same day” appointed in the divine promise, “it came to pass, that all the hosts of the Lord went out from the land of Egypt.” Exodus 12:41. So in heaven’s council the hour for the coming of Christ had been determined. When the great clock of time pointed to that hour, Jesus was born in Bethlehem.