Theodore Beza
15:2 And Abram said, {a} Lord GOD, what wilt thou give me, seeing I go childless, and the steward of my house [is] this Eliezer of Damascus?
(a) His fear was not only lest he should not have children, but lest the promise of the blessed seed should not be accomplished in him.
15:8 And he said, Lord GOD, {b} whereby shall I know that I shall inherit it?
(b) This is a particular motion of God’s Spirit, which is not lawful for all to follow, in asking signs: but was permitted for some by a peculiar motion, as to Gideon and Ezekiel.
15:10 And he took unto him all these, and {c} divided them in the midst, and laid each piece one against another: but the birds divided he not.
(c) This was the old custom in making covenants, Jeremiah 39:18, to which God added these conditions, that Abram’s posterity would be as torn in pieces, but after they would be rejoined: also that it would be assaulted, but yet delivered.
15:13 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.
15:16 But in the fourth generation they shall come hither again: for the {e} iniquity of the Amorites [is] not yet full.
(e) Though God tolerates the wicked for a time, yet his vengeance falls on them when the measure of their wickedness is full.