Know, know thou. - Know certainly. This responds to Abram's question, Whereby shall I know? Genesis 15:8. Four hundred years are to elapse before the seed of Abram shall actually proceed to take possession of the land. This interval can only commence when the seed is born; that is, at the birth of Isaac, when Abram was a hundred years of age and therefore thirty years after the call. During this interval they are to be, "first, strangers in a land not theirs" for one hundred and ninety years; and then for the remaining two hundred and ten years in Egypt: at first, servants, with considerable privilege and position; and at last, afflicted serfs, under a hard and cruel bondage. At the end of this period Pharaoh and his nation were visited with a succession of tremendous judgments, and Israel went out free from bondage "with great wealth" Exodus 12-14. "Go to thy fathers." This implies that the fathers, though dead, still exist. To go from one place to another implies, not annihilation, but the continuance of existence. The doctrine of the soul's perpetual existence is here intimated. Abram died in peace and happiness, one hundred and fifteen years before the descent into Egypt.

Four hundred years - "Which began," says Mr. Ainsworth, "when Ishmael, son of Hagar, mocked and persecuted Isaac, Genesis 21:9; Galatians 4:29; which fell out thirty years after the promise, Genesis 12:3; which promise was four hundred and thirty years before the law, Galatians 3:17; and four hundred and thirty years after that promise came Israel out of Egypt, Exodus 12:41."

And he said unto Abram,.... While he was in a deep sleep; this he said to him in a vision of prophecy:

know of a surety, or "in knowing thou shall or mayest know" (n); and be assured of it, being now told it by the Lord himself, who foreknows all things that ever come to pass; many of which he acquaints his people with beforehand, nor would he hide from Abram his friend what should befall his posterity, as follows:

that thy seed shall be a stranger in a land that is not theirs; this prophecy could not take place at this time, since Abram had then no seed; but at the birth of Isaac, in whom his seed was called, who sojourned, or was a stranger in Gerar, a part of the land of Canaan, as Jacob also in the same land, Genesis 36:3; as well as he and his posterity sojourned or lived as strangers in the land of Ham, in Egypt, Psalm 105:23; and neither of these countries were theirs; for though there was a grant of Canaan to Abram and his seed, yet it was not in possession; though a land of promise, it was a strange land, a land of their pilgrimage, and where all the patriarchs lived in it as such, see Exodus 6:4,

and shall serve them; the inhabitants of the land not theirs, that is, the Canaanites and the Egyptians, especially the latter; and these they served after the death of Joseph, by whom their lives were made bitter with hard bondage:

and they shall afflict them four hundred years; this term "four hundred years" is not to be joined either with the word "afflict" or "serve"; for their hard servitude and severe affliction did not last long, but a few years at most; but with the phrase, "a stranger in a land not theirs"; and the rest is to be included in a parenthesis thus, and "thy seed shall be a stranger in the land not theirs (and shall serve them, and they shall afflict them) four hundred years"; so long they should be strangers and sojourners, as they were partly in the land of Canaan, and partly in the land of Egypt, neither of which were in their own land, however not in possession; within which space of time they would be in a state of subjection and servitude, and be greatly afflicted and oppressed, as they were particularly by the Egyptians before their deliverance from them, see Exodus 1:11. These four hundred years, as before observed, are to be reckoned from the birth of Isaac to the Israelites going out of Egypt, and are counted by Jarchi thus; Isaac was sixty years of age when Jacob was born, and Jacob when he went down into Egypt was one hundred and thirty, which make one hundred and ninety; and the Israelites were in Egypt two hundred and ten years, which complete the sum of four hundred: according to Eusebius, there were four hundred and five years from the birth of Isaac to the Exodus of Israel; but the round number is only given, as is very usual; and though the sojourning of the Israelites is said to be four hundred and thirty years, Exodus 12:40, this takes in the sojourning of Abram in that land, who entered into it sixty five years before the birth of Isaac, which added to four hundred and five, the sum total is four hundred and thirty; for Abram was seventy five years of age when he left Haran and went to Canaan, and Isaac was born when he was an hundred years old, see Genesis 12:4.

(n) "cognoscendo cognosces", Pagninus, Montanus; so Schmidt.

And he said unto Abram, Know of a surety that thy seed shall be a stranger in a land that is not theirs, and shall serve them; and they shall afflict them {d} four hundred years;

(d) Counting from the birth of Isaac to their departure of Egypt: Which declares that God will allow his to be afflicted in this world.

15:13 Thy seed shall be strangers - So they were in Canaan first, Psa 105:11,12, and afterwards in Egypt: before they were lords of their own land, they were strangers in a strange land. The inconveniences of an unsettled state make a happy settlement the more welcome. Thus the heirs of heaven are first strangers on earth. And them they shall serve - So they did the Egyptians, Exo 1:13. See how that which was the doom of the Canaanites, Gen 9:25, proves the distress of Abram's seed: they are made to serve; but with this difference, the Canaanites serve under a curse, the Hebrews under a blessing. And they shall afflict them - See Exo 1:11. Those that are blessed and beloved of God are often afflicted by wicked men. This persecution began with mocking, when Ishmael the son of an Egyptian, persecuted Isaac, Gen 21:9, and it came at last to murder, the basest of murders, that of their new born children; so that more or less it continued 400 years.

15:12-16 A deep sleep fell upon Abram; with this sleep a horror of great darkness fell upon him: a sudden change. The children of light do not always walk in the light. Several things were then foretold. 1. The suffering state of Abram's seed for a long time. They shall be strangers. The heirs of heaven are strangers on earth. They shall be servants; but Canaanites serve under a curse, the Hebrews under a blessing. They shall be suffers. Those that are blessed and beloved of God, are often sorely afflicted by wicked men. 2. The judgment of the enemies of Abram's seed. Though God may allow persecutors and oppressors to trample upon his people a great while, he will certainly reckon with them at last. 3. That great event, the deliverance of Abram's seed out of Egypt, is here foretold. 4. Their happy settlement in Canaan. They shall come hither again. The measure of sin fills gradually. Some people's measure of sin fills slowly. The knowledge of future events would seldom add to our comfort. In the most favoured families, and most happy lives, there are so many afflictions, that it is merciful in God to conceal what will befall us and ours.